Zeina Abdallah, James W. Pomeroy, Nicolas Blasakis, Athanasios Baltopoulos, Martin Kuball
Thermal interface materials are crucial to minimize the thermal resistance between a semiconductor device and a heat sink, especially for high-power electronic devices, which are susceptible to self-heating-induced failures. The effectiveness of these interface materials depends on their low thermal contact resistance coupled with high thermal conductivity. Various characterization techniques are used to determine the thermal properties of the thermal interface materials. However, their bulk or free-standing thermal properties are typically assessed rather than their thermal performance when applied as a thin layer in real application. In this study, we introduce a low-frequency range frequency domain thermoreflectance method that can measure the effective thermal conductivity and volumetric heat capacity of thermal interface materials simultaneously in situ, illustrated on silver-filled thermal interface material samples, offering a distinct advantage over traditional techniques such as ASTM D5470. Monte Carlo fitting is used to quantify the thermal conductivities and heat capacities and their uncertainties, which are compared to a more efficient least-squares method.
{"title":"Simultaneous Measurement of Thermal Conductivity and Volumetric Heat Capacity of Thermal Interface Materials Using Thermoreflectance","authors":"Zeina Abdallah, James W. Pomeroy, Nicolas Blasakis, Athanasios Baltopoulos, Martin Kuball","doi":"10.1021/acsaelm.4c00691","DOIUrl":"https://doi.org/10.1021/acsaelm.4c00691","url":null,"abstract":"Thermal interface materials are crucial to minimize the thermal resistance between a semiconductor device and a heat sink, especially for high-power electronic devices, which are susceptible to self-heating-induced failures. The effectiveness of these interface materials depends on their low thermal contact resistance coupled with high thermal conductivity. Various characterization techniques are used to determine the thermal properties of the thermal interface materials. However, their bulk or free-standing thermal properties are typically assessed rather than their thermal performance when applied as a thin layer in real application. In this study, we introduce a low-frequency range frequency domain thermoreflectance method that can measure the effective thermal conductivity and volumetric heat capacity of thermal interface materials simultaneously in situ, illustrated on silver-filled thermal interface material samples, offering a distinct advantage over traditional techniques such as ASTM D5470. Monte Carlo fitting is used to quantify the thermal conductivities and heat capacities and their uncertainties, which are compared to a more efficient least-squares method.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141518259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One effective approach to overcoming the efficiency limits of triplet–triplet fusion (TTF)-based blue organic light-emitting diodes is to utilize the efficiency enhancement layer (EEL), which can increase efficiency through simple modifications in the device structure. However, the physical mechanism of the EEL, particularly exciton dynamics, has not been thoroughly investigated. In this study, the exciton utilization efficiency (EUE) was calculated by considering the host and EEL as individual emission components to analyze the exciton dynamics of the EEL. The materials that exhibit high-lying reverse intersystem crossing (hRISC) characteristics 2-(4-(10-(3-(9H-carbazol-9-yl)phenyl)anthracen-9-yl)phenyl)-1-phenyl-1H-phenanthro[9,10-d]imidazole (PAC) and 5-(4-(10-phenylanthracen-9-yl)phenyl)-5H-benzofuro[3,2-c]carbazole (ATDBF) were used as an EEL. The maximum external quantum efficiency (EQEmax) of the device without utilizing the EEL was measured at 3.0%. However, when PAC and ATDBF were utilized as the EEL in the device, the EQEmax significantly increased to 4.4 and 4.5%, respectively, resulting in an efficiency improvement of approximately 47–50% compared to when the EEL was not used. To ascertain whether the efficiency enhancement is induced through the hRISC process of the EEL, transient electroluminescence and magnetoelectroluminescence measurements were carried out. The results indicated that the triplets harvested into radiative singlets in the EEL device occurred through the TTF and hRISC processes. Finally, numerical simulations were carried out to evaluate the efficiency contributions from various mechanisms in the nondoped device, including TTF induced from the host (ηTTF.H), TTF induced from the EEL (ηTTF.E), and hRISC induced from the EEL (ηhRISC.E) in addition to 25% of EUE from singles via hole–electron recombination. The calculated ηTTF.H, ηTTF.E, and ηhRISC.E were 3.8, 0.6, and 4.7% for the PAC-based device and 5.5, 0.9, and 12.3% for the ATDBF-based device, respectively. Consequently, while the device using the host alone exhibited an EUE of 31.8%, the incorporation of PAC and ATDBF elevated the EUE to 34.1 and 43.7%, respectively, highlighting significantly enhanced EUE.
要克服基于三重三重融合（TTF）的蓝色有机发光二极管的效率限制，一种有效的方法是利用效率增强层（EEL），它可以通过简单地改变器件结构来提高效率。然而，EEL 的物理机制，尤其是激子动力学，尚未得到深入研究。在本研究中，通过将宿主和 EEL 视为单独的发射成分来计算激子利用效率（EUE），从而分析 EEL 的激子动力学。研究采用了具有高位反向系统间交叉（hRISC）特性的材料 2-(4-(10-(3-(9H-咔唑-9-基)苯基)蒽-9-基)苯基)-1-苯基-1H-菲罗[9,10-d]咪唑（PAC）和 5-(4-(10-苯基蒽-9-基)苯基)-5H-苯并呋喃[3,2-c]咔唑（ATDBF）作为 EEL。在不使用 EEL 的情况下，设备的最大外部量子效率（EQEmax）为 3.0%。然而，当 PAC 和 ATDBF 用作器件中的 EEL 时，EQEmax 分别显著提高到 4.4% 和 4.5%，与不使用 EEL 时相比，效率提高了约 47-50%。为了确定效率的提高是否是通过 EEL 的 hRISC 过程引起的，我们进行了瞬态电致发光和磁致发光测量。结果表明，在 EEL 器件中，通过 TTF 和 hRISC 过程可将三重子收获为辐射单子。最后，我们进行了数值模拟，以评估非掺杂器件中各种机制的效率贡献，包括宿主诱导的 TTF（ηTTF.H）、EEL 诱导的 TTF（ηTTF.E）和 EEL 诱导的 hRISC（ηhRISC.E），以及通过空穴-电子重组产生的 25% 的单体 EUE。计算得出的 ηTTF.H、ηTTF.E 和 ηhRISC.E 分别为：基于 PAC 的器件为 3.8%、0.6% 和 4.7%，基于 ATDBF 的器件为 5.5%、0.9% 和 12.3%。因此，虽然单独使用主机的设备的 EUE 为 31.8%，但加入 PAC 和 ATDBF 后，EUE 分别提高到 34.1% 和 43.7%，突出表明 EUE 显著增强。
{"title":"Quantitative Analysis of Exciton Dynamics: Investigating the Role of the Efficiency-Enhancement Layer for Blue Fluorescent Organic Light-Emitting Diodes","authors":"Bum June Park, Ki Ju Kim, Taekyung Kim","doi":"10.1021/acsaelm.4c00695","DOIUrl":"https://doi.org/10.1021/acsaelm.4c00695","url":null,"abstract":"One effective approach to overcoming the efficiency limits of triplet–triplet fusion (TTF)-based blue organic light-emitting diodes is to utilize the efficiency enhancement layer (EEL), which can increase efficiency through simple modifications in the device structure. However, the physical mechanism of the EEL, particularly exciton dynamics, has not been thoroughly investigated. In this study, the exciton utilization efficiency (EUE) was calculated by considering the host and EEL as individual emission components to analyze the exciton dynamics of the EEL. The materials that exhibit high-lying reverse intersystem crossing (hRISC) characteristics 2-(4-(10-(3-(9<i>H</i>-carbazol-9-yl)phenyl)anthracen-9-yl)phenyl)-1-phenyl-1<i>H</i>-phenanthro[9,10-<i>d</i>]imidazole (PAC) and 5-(4-(10-phenylanthracen-9-yl)phenyl)-5<i>H</i>-benzofuro[3,2-<i>c</i>]carbazole (ATDBF) were used as an EEL. The maximum external quantum efficiency (EQE<sub>max</sub>) of the device without utilizing the EEL was measured at 3.0%. However, when PAC and ATDBF were utilized as the EEL in the device, the EQ<i>E</i><sub>max</sub> significantly increased to 4.4 and 4.5%, respectively, resulting in an efficiency improvement of approximately 47–50% compared to when the EEL was not used. To ascertain whether the efficiency enhancement is induced through the hRISC process of the EEL, transient electroluminescence and magnetoelectroluminescence measurements were carried out. The results indicated that the triplets harvested into radiative singlets in the EEL device occurred through the TTF and hRISC processes. Finally, numerical simulations were carried out to evaluate the efficiency contributions from various mechanisms in the nondoped device, including TTF induced from the host (η<sub>TTF.H</sub>), TTF induced from the EEL (η<sub>TTF.E</sub>), and hRISC induced from the EEL (η<sub>hRISC.E</sub>) in addition to 25% of EUE from singles via hole–electron recombination. The calculated η<sub>TTF.H</sub>, η<sub>TTF.E</sub>, and η<sub>hRISC.E</sub> were 3.8, 0.6, and 4.7% for the PAC-based device and 5.5, 0.9, and 12.3% for the ATDBF-based device, respectively. Consequently, while the device using the host alone exhibited an EUE of 31.8%, the incorporation of PAC and ATDBF elevated the EUE to 34.1 and 43.7%, respectively, highlighting significantly enhanced EUE.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dark current and response speed matter a lot in UV detection. TiO2 MSM UV detectors offer many positive attributes, including chemical stability and excellent absorption in the UV region. However, they also have a high dark current and a poor response time. To get around these drawbacks, an MSM UV detector based on the CuTiO3/TiO2 type-I heterojunction was created in this work. The introduction of high-dielectric perovskite CuTiO3 reduces carriers and thus leads to a low dark current (8.06 × 10–12 A). Furthermore, type-I heterojunction properties of the CuTiO3/TiO2 heterojunction significantly restrict the recombination process of photogenerated carriers in TiO2, improving response and recovery times (78 and 93 ms). The findings suggested that high-performance UV photodetectors might be created by combining conventional wide-band-gap semiconductor materials with high-dielectric perovskite CuTiO3.
{"title":"CuTiO3/TiO2 MSM UV Photodetector with a Type-I Heterojunction for Rapid and Low-Power Detection","authors":"Yupeng Zhang, Zhengyu Bi, Xinyan Liu, Yan Ma, Shengping Ruan, Ruiliang Xu, Jingran Zhou","doi":"10.1021/acsaelm.4c00950","DOIUrl":"https://doi.org/10.1021/acsaelm.4c00950","url":null,"abstract":"Dark current and response speed matter a lot in UV detection. TiO<sub>2</sub> MSM UV detectors offer many positive attributes, including chemical stability and excellent absorption in the UV region. However, they also have a high dark current and a poor response time. To get around these drawbacks, an MSM UV detector based on the CuTiO<sub>3</sub>/TiO<sub>2</sub> type-I heterojunction was created in this work. The introduction of high-dielectric perovskite CuTiO<sub>3</sub> reduces carriers and thus leads to a low dark current (8.06 × 10<sup>–12</sup> A). Furthermore, type-I heterojunction properties of the CuTiO<sub>3</sub>/TiO<sub>2</sub> heterojunction significantly restrict the recombination process of photogenerated carriers in TiO<sub>2</sub>, improving response and recovery times (78 and 93 ms). The findings suggested that high-performance UV photodetectors might be created by combining conventional wide-band-gap semiconductor materials with high-dielectric perovskite CuTiO<sub>3</sub>.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141518260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Arianna Nigro, Eric Jutzi, Fabian Oppliger, Franco De Palma, Christian Olsen, Alicia Ruiz-Caridad, Gerard Gadea, Pasquale Scarlino, Ilaria Zardo, Andrea Hofmann
One of the most promising platforms for the realization of spin-based quantum computing are planar germanium quantum wells embedded between silicon–germanium barriers. To achieve comparably thin stacks with little surface roughness, this type of heterostructure can be grown using the so-called reverse linear grading approach, where the growth starts with a virtual germanium substrate followed by a graded silicon–germanium alloy with an increasing silicon content. However, the compatibility of such reverse-graded heterostructures with superconducting microwave resonators has not yet been demonstrated. Here, we report on the successful realization of well-controlled double quantum dots and high-quality coplanar waveguide resonators on the same reverse-graded Ge/SiGe heterostructure.
{"title":"Demonstration of Microwave Resonators and Double Quantum Dots on Optimized Reverse-Graded Ge/SiGe Heterostructures","authors":"Arianna Nigro, Eric Jutzi, Fabian Oppliger, Franco De Palma, Christian Olsen, Alicia Ruiz-Caridad, Gerard Gadea, Pasquale Scarlino, Ilaria Zardo, Andrea Hofmann","doi":"10.1021/acsaelm.4c00654","DOIUrl":"https://doi.org/10.1021/acsaelm.4c00654","url":null,"abstract":"One of the most promising platforms for the realization of spin-based quantum computing are planar germanium quantum wells embedded between silicon–germanium barriers. To achieve comparably thin stacks with little surface roughness, this type of heterostructure can be grown using the so-called reverse linear grading approach, where the growth starts with a virtual germanium substrate followed by a graded silicon–germanium alloy with an increasing silicon content. However, the compatibility of such reverse-graded heterostructures with superconducting microwave resonators has not yet been demonstrated. Here, we report on the successful realization of well-controlled double quantum dots and high-quality coplanar waveguide resonators on the same reverse-graded Ge/SiGe heterostructure.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141518263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amit Kumar Verma, Rachana Gupta, Shashi Prakash, Andrei Gloskovskii, Shailesh Kalal, Priyanshi Tiwari, Varimalla Raghavendra Reddy, Rajeev Rawat, Mukul Gupta
In this work, we present a systematic study of superconducting vanadium mononitride (VN) thin films that were simultaneously grown on single crystalline MgO (100) and amorphous SiO2 substrates. The structure of both samples was probed using X-ray diffraction measurements under different geometries, i.e., specular, off-specular, and ϕ-scan. It was found that the lattice parameter (LP) of VN films grown on SiO2 was 4.098(7) Å, while on MgO, it was slightly larger at 4.124(2) Å. Though the LP of both samples is within the experimentally obtained and theoretically predicted values, the obtained difference suggests that the polycrystalline VN has a tensile strain as compared to the epitaxial film. The effect of such strain is more clearly reflected on the superconducting transition temperature (TC) and normal state electrical resistivity (ρn). In case of the epitaxial VN sample, the TC was at 8.1 K, while in the polycrystalline sample, it was at 5.2 K. The ρn was also found to be significantly smaller in epitaxial films, suggesting a better crystalline quality. We performed X-ray absorption and hard X-ray photoelectron spectroscopy measurements to probe the electronic structure. It was found that the surface region of polycrystalline or epitaxial samples remains unaffected by such strains. However, high magnetic field resistivity measurements exhibited a two-step TC in the epitaxial film which originates due to formation of a thin strained region formed during the initial stages of growth. Our in situ reflection high energy electron diffraction measurements confirmed that the initial stages of growth is strained due to lattice mismatch of about +2.13% between MgO and VN. Overall, this comparative study of epitaxial and polycrystalline samples elucidates the role of stress and strain on the structural, electronic, and superconducting properties of VN thin films.
在这项工作中，我们对同时生长在单晶氧化镁（100）和无定形二氧化硅基底上的超导单氮化钒（VN）薄膜进行了系统研究。在不同的几何条件下，即镜面、非镜面和ϕ扫描条件下，使用 X 射线衍射测量探究了这两种样品的结构。结果发现，在二氧化硅上生长的 VN 薄膜的晶格参数（LP）为 4.098(7) Å，而在氧化镁上生长的 VN 薄膜的晶格参数（LP）稍大，为 4.124(2) Å。这种应变对超导转变温度（TC）和正常状态电阻率（ρn）的影响更为明显。外延 VN 样品的超导转变温度为 8.1 K，而多晶样品的超导转变温度为 5.2 K。我们进行了 X 射线吸收和硬 X 射线光电子能谱测量，以探测电子结构。结果发现，多晶或外延样品的表面区域不受这种应变的影响。然而，高磁场电阻率测量显示，外延薄膜中存在两级 TC，这是由于在生长的初始阶段形成了一个薄的应变区域。我们的原位反射高能电子衍射测量结果证实，生长的初始阶段由于氧化镁和 VN 之间约 +2.13% 的晶格失配而产生应变。总之，这项关于外延和多晶样品的比较研究阐明了应力和应变对 VN 薄膜的结构、电子和超导特性的影响。
{"title":"Structure and Superconductivity of Epitaxial and Polycrystalline VN Thin Films","authors":"Amit Kumar Verma, Rachana Gupta, Shashi Prakash, Andrei Gloskovskii, Shailesh Kalal, Priyanshi Tiwari, Varimalla Raghavendra Reddy, Rajeev Rawat, Mukul Gupta","doi":"10.1021/acsaelm.4c00540","DOIUrl":"https://doi.org/10.1021/acsaelm.4c00540","url":null,"abstract":"In this work, we present a systematic study of superconducting vanadium mononitride (VN) thin films that were simultaneously grown on single crystalline MgO (100) and amorphous SiO<sub>2</sub> substrates. The structure of both samples was probed using X-ray diffraction measurements under different geometries, i.e., specular, off-specular, and ϕ-scan. It was found that the lattice parameter (LP) of VN films grown on SiO<sub>2</sub> was 4.098(7) Å, while on MgO, it was slightly larger at 4.124(2) Å. Though the LP of both samples is within the experimentally obtained and theoretically predicted values, the obtained difference suggests that the polycrystalline VN has a tensile strain as compared to the epitaxial film. The effect of such strain is more clearly reflected on the superconducting transition temperature (<i>T</i><sub>C</sub>) and normal state electrical resistivity (ρ<sub><i>n</i></sub>). In case of the epitaxial VN sample, the <i>T</i><sub>C</sub> was at 8.1 K, while in the polycrystalline sample, it was at 5.2 K. The ρ<sub><i>n</i></sub> was also found to be significantly smaller in epitaxial films, suggesting a better crystalline quality. We performed X-ray absorption and hard X-ray photoelectron spectroscopy measurements to probe the electronic structure. It was found that the surface region of polycrystalline or epitaxial samples remains unaffected by such strains. However, high magnetic field resistivity measurements exhibited a two-step <i>T</i><sub>C</sub> in the epitaxial film which originates due to formation of a thin strained region formed during the initial stages of growth. Our in situ reflection high energy electron diffraction measurements confirmed that the initial stages of growth is strained due to lattice mismatch of about +2.13% between MgO and VN. Overall, this comparative study of epitaxial and polycrystalline samples elucidates the role of stress and strain on the structural, electronic, and superconducting properties of VN thin films.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141518261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the field of electromagnetic wave (EMW) absorption, the development of nonmagnetic materials with strong absorptive performance, low filling ratio, and wide bandwidth is of significant importance. In this work, five morphologies of In2O3 nanomaterials are prepared by simple hydrothermal and annealing processes. The morphologies of products (including the lamellar flower-, lychee-, cheese-, nanocube-, and urchin-like In2O3) are obtained by using different surfactants. The experimental results indicate that the lamellar flower-like In2O3 has a minimum reflection loss (RLmin) of −52.04 dB (1.74 mm) and an effective absorption bandwidth (EAB) of 5.97 GHz (1.92 mm). Correspondingly, the RLmin and EAB of lychee-like In2O3 are −70.61 dB (2.55 mm) and 5.57 GHz (1.72 mm), respectively. A large specific surface area about lamellar flower-like In2O3 can effectively increase the reflection and scattering paths of EMW inside the absorbing material, which is beneficial for the attenuation of EMW. This work not only demonstrates the great potential of In2O3 in practical EMW absorption applications but also extends the research on nonmagnetic materials in the EMW absorption field.
{"title":"Morphology-Controlled In2O3 Nanomaterials with Excellent Electromagnetic Wave Absorption Properties","authors":"Bonan Liu, Chuchu Yan, Qianqian Ren, Wei Li, Weihang Ma, Zhihao Liu, Han Zhang, Hongyang Zhu, Zhiyong Zhang, Wu Zhao, Yingnan Wang","doi":"10.1021/acsaelm.4c00830","DOIUrl":"https://doi.org/10.1021/acsaelm.4c00830","url":null,"abstract":"In the field of electromagnetic wave (EMW) absorption, the development of nonmagnetic materials with strong absorptive performance, low filling ratio, and wide bandwidth is of significant importance. In this work, five morphologies of In<sub>2</sub>O<sub>3</sub> nanomaterials are prepared by simple hydrothermal and annealing processes. The morphologies of products (including the lamellar flower-, lychee-, cheese-, nanocube-, and urchin-like In<sub>2</sub>O<sub>3</sub>) are obtained by using different surfactants. The experimental results indicate that the lamellar flower-like In<sub>2</sub>O<sub>3</sub> has a minimum reflection loss (RL<sub>min</sub>) of −52.04 dB (1.74 mm) and an effective absorption bandwidth (EAB) of 5.97 GHz (1.92 mm). Correspondingly, the RL<sub>min</sub> and EAB of lychee-like In<sub>2</sub>O<sub>3</sub> are −70.61 dB (2.55 mm) and 5.57 GHz (1.72 mm), respectively. A large specific surface area about lamellar flower-like In<sub>2</sub>O<sub>3</sub> can effectively increase the reflection and scattering paths of EMW inside the absorbing material, which is beneficial for the attenuation of EMW. This work not only demonstrates the great potential of In<sub>2</sub>O<sub>3</sub> in practical EMW absorption applications but also extends the research on nonmagnetic materials in the EMW absorption field.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141518264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Laser-induced graphene (LIG) shows broad application prospects in flexible pressure sensors due to its adjustable electrical properties, good economy, and roll-to-roll compatibility. Incorporating an appropriate nanomaterial into LIG is an effective method to significantly improve its pressure-sensitive properties. In this study, we report an MXene nanoengineered LIG for highly sensitive flexible piezoresistive sensors. The photochemically synthesized MXene-derived nanosheets are anchored in the porous network of LIG to form a MXene/graphene heterostructure (LIMG) by in situ coconversion of MXene/Polyamide acid (PAA) composite under laser irradiation. Benefiting from the conductive paths created by MXene nanosheets in LIG matrix and the stable chemical bonding of MXene-LIG interfaces, the LIMG sensor exhibits a sensitivity of 20 kPa–1, which is 567% higher than the LIG sensor. Meanwhile, the sensor has a wide range of 80 kPa, fast response/recovery time of 42/28 ms, and excellent stability over 4000 cycles. In practical applications, the LIMG sensor effectively monitors human physiological signals, such as voice, pulse, and respiration, proving its broad prospects in wearable health monitoring. Furthermore, the preparation of two-dimensional/three-dimensional (2D/3D) heterostructures by one-step laser coconversion is expected to promote the development of nanomaterial synthesis technology.
激光诱导石墨烯（LIG）具有可调节的电气性能、良好的经济性和卷对卷兼容性，因此在柔性压力传感器中具有广阔的应用前景。在石墨烯中加入适当的纳米材料是显著改善其压力敏感特性的有效方法。在本研究中，我们报告了一种用于高灵敏柔性压阻传感器的 MXene 纳米工程 LIG。在激光照射下，光化学合成的 MXene 衍生纳米片被锚定在 LIG 的多孔网络中，通过 MXene/Polyamide acid (PAA) 复合材料的原位茧转化形成了 MXene/ 石墨烯异质结构（LIMG）。得益于 MXene 纳米片在 LIG 基体中形成的导电通路以及 MXene-LIG 界面的稳定化学键，LIMG 传感器的灵敏度达到 20 kPa-1，比 LIG 传感器高出 567%。同时，该传感器具有 80 kPa 的宽量程，42/28 ms 的快速响应/恢复时间，以及超过 4000 次循环的出色稳定性。在实际应用中，LIMG 传感器能有效监测语音、脉搏和呼吸等人体生理信号，证明了其在可穿戴健康监测领域的广阔前景。此外，通过一步激光共转化制备二维/三维（2D/3D）异质结构有望推动纳米材料合成技术的发展。
{"title":"Laser Thermochemical Synthesis of MXene/Graphene Heterostructure for a Highly Sensitive Flexible Pressure Sensor","authors":"Yunfan Li, Zezhou Yang, Xiao Chen, Shizhuo Zhang, Shuqi Xu, Peilong Li, Longju Yi, Feng Liu","doi":"10.1021/acsaelm.4c00668","DOIUrl":"https://doi.org/10.1021/acsaelm.4c00668","url":null,"abstract":"Laser-induced graphene (LIG) shows broad application prospects in flexible pressure sensors due to its adjustable electrical properties, good economy, and roll-to-roll compatibility. Incorporating an appropriate nanomaterial into LIG is an effective method to significantly improve its pressure-sensitive properties. In this study, we report an MXene nanoengineered LIG for highly sensitive flexible piezoresistive sensors. The photochemically synthesized MXene-derived nanosheets are anchored in the porous network of LIG to form a MXene/graphene heterostructure (LIMG) by in situ coconversion of MXene/Polyamide acid (PAA) composite under laser irradiation. Benefiting from the conductive paths created by MXene nanosheets in LIG matrix and the stable chemical bonding of MXene-LIG interfaces, the LIMG sensor exhibits a sensitivity of 20 kPa<sup>–1</sup>, which is 567% higher than the LIG sensor. Meanwhile, the sensor has a wide range of 80 kPa, fast response/recovery time of 42/28 ms, and excellent stability over 4000 cycles. In practical applications, the LIMG sensor effectively monitors human physiological signals, such as voice, pulse, and respiration, proving its broad prospects in wearable health monitoring. Furthermore, the preparation of two-dimensional/three-dimensional (2D/3D) heterostructures by one-step laser coconversion is expected to promote the development of nanomaterial synthesis technology.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141518160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haipeng You, Yixiao Chen, Yue Li, Jun Chen, Xiyu Chen, Meifeng Liu, Shuai Dong, Jin Peng
B-site rock salt type ordered double perovskites with general formula A2B′B″X6 have attracted a variety of attention due to remarkable magnetic properties and potential applications in spintronics. Here we report the structural, magnetic, and electronic properties of polycrystalline compounds Ba2MnTeO6 and (Ba0.9X0.1)2MnTeO6 (X = K/La) by powder X-ray diffraction, magnetic susceptibility measurements, specific heat measurements, and X-ray photoelectron spectroscopy. Ba2MnTeO6 is antiferromagnetically ordered below 20 K. Density functional theory calculations show that Ba2MnTeO6 prefers type III antiferromagnetic order with a dominant antiferromagnetic nearest-neighbor exchange and a weak ferromagnetic next-nearest-neighbor exchange. Our Monte Carlo simulations lead to a transition temperature of 28 K, consistent with the experimental results. Upon K+/La3+ cations’ implantation on Ba sites, while (Ba0.9K0.1)2MnTeO6 orders antiferromagnetically at 20 K, (Ba0.9La0.1)2MnTeO6 exhibits superparamagnetism below room temperature, which may originate from oxygen ion adsorptions. These findings reveal the modulation of magnetism for Ba2MnTeO6, which may hint at potential applications of double perovskites in magnetic devices.
通式为 A2B′B″X6 的 B 位岩盐型有序双高晶石因其显著的磁性能和在自旋电子学中的潜在应用而受到广泛关注。在此，我们通过粉末 X 射线衍射、磁感应强度测量、比热测量和 X 射线光电子能谱，报告了多晶化合物 Ba2MnTeO6 和 (Ba0.9X0.1)2MnTeO6 （X = K/La）的结构、磁性和电子特性。密度泛函理论计算表明，Ba2MnTeO6 更倾向于 III 型反铁磁有序，其中反铁磁近邻交换占主导地位，而铁磁近邻交换较弱。蒙特卡洛模拟得出的转变温度为 28 K，与实验结果一致。当 K+/La3+ 阳离子植入 Ba 位点时，(Ba0.9K0.1)2MnTeO6 在 20 K 时具有反铁磁性，而(Ba0.9La0.1)2MnTeO6 在室温以下则表现出超顺磁性，这可能源于氧离子的吸附作用。这些发现揭示了 Ba2MnTeO6 的磁性调制，这可能暗示了双包晶在磁性器件中的潜在应用。
{"title":"Evolution of Magnetism Induced by K+/La3+ Implantations in Double Perovskite Ba2MnTeO6","authors":"Haipeng You, Yixiao Chen, Yue Li, Jun Chen, Xiyu Chen, Meifeng Liu, Shuai Dong, Jin Peng","doi":"10.1021/acsaelm.4c00401","DOIUrl":"https://doi.org/10.1021/acsaelm.4c00401","url":null,"abstract":"<i>B</i>-site rock salt type ordered double perovskites with general formula <i>A</i><sub>2</sub><i>B′B</i>″<i>X</i><sub>6</sub> have attracted a variety of attention due to remarkable magnetic properties and potential applications in spintronics. Here we report the structural, magnetic, and electronic properties of polycrystalline compounds Ba<sub>2</sub>MnTeO<sub>6</sub> and (Ba<sub>0.9</sub>X<sub>0.1</sub>)<sub>2</sub>MnTeO<sub>6</sub> (X = K/La) by powder X-ray diffraction, magnetic susceptibility measurements, specific heat measurements, and X-ray photoelectron spectroscopy. Ba<sub>2</sub>MnTeO<sub>6</sub> is antiferromagnetically ordered below 20 K. Density functional theory calculations show that Ba<sub>2</sub>MnTeO<sub>6</sub> prefers type III antiferromagnetic order with a dominant antiferromagnetic nearest-neighbor exchange and a weak ferromagnetic next-nearest-neighbor exchange. Our Monte Carlo simulations lead to a transition temperature of 28 K, consistent with the experimental results. Upon K<sup>+</sup>/La<sup>3+</sup> cations’ implantation on Ba sites, while (Ba<sub>0.9</sub>K<sub>0.1</sub>)<sub>2</sub>MnTeO<sub>6</sub> orders antiferromagnetically at 20 K, (Ba<sub>0.9</sub>La<sub>0.1</sub>)<sub>2</sub>MnTeO<sub>6</sub> exhibits superparamagnetism below room temperature, which may originate from oxygen ion adsorptions. These findings reveal the modulation of magnetism for Ba<sub>2</sub>MnTeO<sub>6</sub>, which may hint at potential applications of double perovskites in magnetic devices.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141518158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ketong Yang, Minhyun Jung, Taeseung Jung, Jae Seok Yoon, Junghyeon Hwang, Hunbeom Shin, Seungyeob Kim, Chaeheon Kim, Sanghun Jeon
Hafnia ferroelectrics are gaining significance in nonvolatile memory, logic devices, and neuromorphic computing because of their rapid switching speed, exceptional reliability, and low-voltage operations. In addition, it demonstrates exceptional process compatibility with advanced thin film techniques such as atomic layer deposition (ALD). Conventical radio frequency (RF) plasma-enhanced (PE) ALD offers various advantages including enhanced reaction rates, improved film characteristics, and a lower process temperature. However, the inevitable plasma damages and interfacial defects that occur as a result of the RF PE-ALD process have a major impact on the polarization hysteresis features of hafnia ferroelectrics. In our study, we fabricated a Hf0.5 Zr0.5O2 (HZO) film utilizing a very high frequency (VHF) (∼100 MHz) PEALD. This approach demonstrated greater effectiveness in radical reactions and efficiently mitigated plasma-induced damage in the HZO film. The utilization of high-frequency plasma enhances stability and exhibits excellent ferroelectric characteristics. Specifically, it led to an increase in the interfacial capacitance, a decrease in the wake-up effect, and a reduction in the proportion of suboxide in HZO films. Our observations revealed exceptional switching speed (60 ns) and outstanding reliability (1010 cycles) along with a retention rate of 94% over a span of 10 years at a temperature of 85 °C. The research demonstrates that VHF PE-ALD is a viable method for creating hafnia thin films with reduced defects at the interface.
{"title":"Unlocking the Potential of Hafnia Ferroelectrics: Achieving High Reliability via Plasma Frequency Modulation in Very High-Frequency Plasma-Enhanced Atomic Layer Deposition","authors":"Ketong Yang, Minhyun Jung, Taeseung Jung, Jae Seok Yoon, Junghyeon Hwang, Hunbeom Shin, Seungyeob Kim, Chaeheon Kim, Sanghun Jeon","doi":"10.1021/acsaelm.4c00630","DOIUrl":"https://doi.org/10.1021/acsaelm.4c00630","url":null,"abstract":"Hafnia ferroelectrics are gaining significance in nonvolatile memory, logic devices, and neuromorphic computing because of their rapid switching speed, exceptional reliability, and low-voltage operations. In addition, it demonstrates exceptional process compatibility with advanced thin film techniques such as atomic layer deposition (ALD). Conventical radio frequency (RF) plasma-enhanced (PE) ALD offers various advantages including enhanced reaction rates, improved film characteristics, and a lower process temperature. However, the inevitable plasma damages and interfacial defects that occur as a result of the RF PE-ALD process have a major impact on the polarization hysteresis features of hafnia ferroelectrics. In our study, we fabricated a Hf<sub>0.5</sub> Zr<sub>0.5</sub>O<sub>2</sub> (HZO) film utilizing a very high frequency (VHF) (∼100 MHz) PEALD. This approach demonstrated greater effectiveness in radical reactions and efficiently mitigated plasma-induced damage in the HZO film. The utilization of high-frequency plasma enhances stability and exhibits excellent ferroelectric characteristics. Specifically, it led to an increase in the interfacial capacitance, a decrease in the wake-up effect, and a reduction in the proportion of suboxide in HZO films. Our observations revealed exceptional switching speed (60 ns) and outstanding reliability (10<sup>10</sup> cycles) along with a retention rate of 94% over a span of 10 years at a temperature of 85 °C. The research demonstrates that VHF PE-ALD is a viable method for creating hafnia thin films with reduced defects at the interface.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MoS2, being an attractive two-dimensional (2-D) material, has gradually become a research hotspot in recent years. Herein, the MoS2–x thin films are grown through a chemical vapor deposition technique by varying the sulfurization temperature from 700 to 900 °C. X-ray diffraction profile reveals the highly crystalline nature of the sample grown at 800 °C and results in the improved directional orientation of the atoms. A decrement in the intensity of the S 2p peak for the thin film sulfurized at 800 °C signifies the diffusion of the sulfur atoms into the molybdenum atoms, prominently resulting in the development of a nanostructured morphology. The formation of an ohmic contact between the photoactive material and the electrode results in the fast transportation of the charge carriers through the metal-semiconductor interface. The sample grown at 800 °C, achieves a high photocurrent, a sharp rise time, and a superior responsivity of 112.49 μA, 35 ms, and 2.69 A/W, respectively, under the illumination of the visible light (λ = 550 nm) and optical power density of 0.1667 mW/cm2 attributed to its higher crystalline nature and formation of prominent nanoflake-structured morphology. Finally, with superior figures of merit, the fabricated photodetector signifies its potential for application in optoelectronics devices.
MoS2 是一种极具吸引力的二维（2-D）材料，近年来逐渐成为研究热点。本文采用化学气相沉积技术，通过改变硫化温度（700 至 900 °C）来生长 MoS2-x 薄膜。X 射线衍射图显示了 800 °C 下生长的样品的高结晶性，并改善了原子的定向取向。在 800 ℃ 下硫化的薄膜的 S 2p 峰强度降低，表明硫原子扩散到了钼原子中，显著形成了纳米结构形态。光活性材料与电极之间形成的欧姆接触使电荷载流子能够快速通过金属-半导体界面。在可见光（λ = 550 nm）和 0.1667 mW/cm2 光功率密度的照射下，在 800 °C 下生长的样品实现了较高的光电流、较快的上升时间和较高的响应率，分别为 112.49 μA、35 ms 和 2.69 A/W ，这归功于其较高的结晶性和突出的纳米片结构形态的形成。最后，所制造的光电探测器具有优异的性能数据，表明其在光电设备中的应用潜力。
{"title":"Surface Morphology Evolution of MoS2–x by Growth Temperature and Its Effect on Photodetector Properties","authors":"Anibrata Mondal, Y. Ashok Kumar Reddy","doi":"10.1021/acsaelm.4c00665","DOIUrl":"https://doi.org/10.1021/acsaelm.4c00665","url":null,"abstract":"MoS<sub>2</sub>, being an attractive two-dimensional (2-D) material, has gradually become a research hotspot in recent years. Herein, the MoS<sub>2–<i>x</i></sub> thin films are grown through a chemical vapor deposition technique by varying the sulfurization temperature from 700 to 900 °C. X-ray diffraction profile reveals the highly crystalline nature of the sample grown at 800 °C and results in the improved directional orientation of the atoms. A decrement in the intensity of the S 2p peak for the thin film sulfurized at 800 °C signifies the diffusion of the sulfur atoms into the molybdenum atoms, prominently resulting in the development of a nanostructured morphology. The formation of an ohmic contact between the photoactive material and the electrode results in the fast transportation of the charge carriers through the metal-semiconductor interface. The sample grown at 800 °C, achieves a high photocurrent, a sharp rise time, and a superior responsivity of 112.49 μA, 35 ms, and 2.69 A/W, respectively, under the illumination of the visible light (λ = 550 nm) and optical power density of 0.1667 mW/cm<sup>2</sup> attributed to its higher crystalline nature and formation of prominent nanoflake-structured morphology. Finally, with superior figures of merit, the fabricated photodetector signifies its potential for application in optoelectronics devices.","PeriodicalId":3,"journal":{"name":"ACS Applied Electronic Materials","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141518161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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