M. Karam, J. Houard, O. Bhorade, I. Blum, A. Vella
Terahertz (THz) radiation with low-energy photons (meV) is used in a wide range of applications, such as microscopy, sensing, and spectroscopy. However, recently, high amplitude THz pulses of MV/cm have been generated and used for electron emission and ion evaporation from field emitters, opening up the possibility of using high amplitude THz pulses for material imaging by THz-assisted atom probe tomography (APT). In this work, we compare the APT analyses of lanthanum hexaboride (LaB6) samples using a femtosecond near-infrared laser with those obtained using high-amplitude single-cycle THz pulses. The atomic-scale characterization of stoichiometric LaB6 is challenging in laser-assisted APT due to the detection losses of boron ions. Here, we show that the THz radiation reduces the emission of molecular ions and multiple detection events, and it increases the charge state of the emitted ions. All these effects result in an improvement in boron detection. Furthermore, the emission dynamics of boron and lanthanum ions differ in their evaporation times when using THz radiation. This work emphasizes the ability of high-amplitude, single-cycle THz pulses to well control material analysis in APT, leading to better results on chemical composition. It also paves the way for the use of this radiation for material manipulation.
{"title":"THz vs NIR laser-assisted atom probe tomography of LaB6 samples","authors":"M. Karam, J. Houard, O. Bhorade, I. Blum, A. Vella","doi":"10.1063/5.0209916","DOIUrl":"https://doi.org/10.1063/5.0209916","url":null,"abstract":"Terahertz (THz) radiation with low-energy photons (meV) is used in a wide range of applications, such as microscopy, sensing, and spectroscopy. However, recently, high amplitude THz pulses of MV/cm have been generated and used for electron emission and ion evaporation from field emitters, opening up the possibility of using high amplitude THz pulses for material imaging by THz-assisted atom probe tomography (APT). In this work, we compare the APT analyses of lanthanum hexaboride (LaB6) samples using a femtosecond near-infrared laser with those obtained using high-amplitude single-cycle THz pulses. The atomic-scale characterization of stoichiometric LaB6 is challenging in laser-assisted APT due to the detection losses of boron ions. Here, we show that the THz radiation reduces the emission of molecular ions and multiple detection events, and it increases the charge state of the emitted ions. All these effects result in an improvement in boron detection. Furthermore, the emission dynamics of boron and lanthanum ions differ in their evaporation times when using THz radiation. This work emphasizes the ability of high-amplitude, single-cycle THz pulses to well control material analysis in APT, leading to better results on chemical composition. It also paves the way for the use of this radiation for material manipulation.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141703536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ryotaro Hayasaka, T. Kanda, Y. Masutake, Duy Khanh Nguyen, N. Hasegawa, Seitaro Inoue, Asato Wada, M. Kitamura, D. Shiga, K. Yoshimatsu, H. Kumigashira
The band alignment at the interface is one of the fundamental parameters for designing electronic devices and artificial functional materials. However, there is no firmly established guideline for oxide heterostructures, limiting the functional design of oxide heterostructures. Here, we provide spectral evidence that the band diagram of oxide heterointerfaces is well described by the Zhong and Hansmann scheme based on the common anion rule [Z. Zhong and P. Hansmann, Phys. Rev. X 7, 011023 (2017)]. By utilizing the elemental selectivity of Ti 2p–3d resonant photoemission for the Ti 3d state near the Fermi level, we directly visualize the presence or absence of charge transfer from the overlayer films to SrTiO3 in prototypical heterointerfaces of SrVO3/SrTiO3 and SrNbO3/SrTiO3. It is found that the charge transfer occurs in SrNbO3/SrTiO3 but not in SrVO3/SrTiO3, as predicted by the Zhong and Hansmann scheme, indicating that the presence or absence, as well as the sign and amount, of interfacial charge transfer is predicted by this scheme. Our findings provide guidelines for designing and controlling the functionalities in oxide nanostructures.
界面带排列是设计电子器件和人工功能材料的基本参数之一。然而，氧化物异质结构并没有牢固确立的准则，这限制了氧化物异质结构的功能设计。在此，我们提供了光谱证据，证明氧化物异质界面的能带图可以用基于共同阴离子规则的钟和汉斯曼方案很好地描述[Z. Zhong and P. Hansmann, Phys. Rev. X 7, 011023 (2017)]。通过利用 Ti 2p-3d 共振光发射对费米水平附近 Ti 3d 态的元素选择性，我们直接观察到在 SrVO3/SrTiO3 和 SrNbO3/SrTiO3 原型异质界面中是否存在从覆盖层薄膜到 SrTiO3 的电荷转移。研究发现，电荷转移发生在 SrNbO3/SrTiO3 中，而不是 SrVO3/SrTiO3 中，正如 Zhong 和 Hansmann 方案所预测的那样。我们的发现为设计和控制氧化物纳米结构的功能性提供了指导。
{"title":"Common anion rule in oxide heterointerfaces: Experimental verification by in situ photoemission spectroscopy","authors":"Ryotaro Hayasaka, T. Kanda, Y. Masutake, Duy Khanh Nguyen, N. Hasegawa, Seitaro Inoue, Asato Wada, M. Kitamura, D. Shiga, K. Yoshimatsu, H. Kumigashira","doi":"10.1063/5.0223269","DOIUrl":"https://doi.org/10.1063/5.0223269","url":null,"abstract":"The band alignment at the interface is one of the fundamental parameters for designing electronic devices and artificial functional materials. However, there is no firmly established guideline for oxide heterostructures, limiting the functional design of oxide heterostructures. Here, we provide spectral evidence that the band diagram of oxide heterointerfaces is well described by the Zhong and Hansmann scheme based on the common anion rule [Z. Zhong and P. Hansmann, Phys. Rev. X 7, 011023 (2017)]. By utilizing the elemental selectivity of Ti 2p–3d resonant photoemission for the Ti 3d state near the Fermi level, we directly visualize the presence or absence of charge transfer from the overlayer films to SrTiO3 in prototypical heterointerfaces of SrVO3/SrTiO3 and SrNbO3/SrTiO3. It is found that the charge transfer occurs in SrNbO3/SrTiO3 but not in SrVO3/SrTiO3, as predicted by the Zhong and Hansmann scheme, indicating that the presence or absence, as well as the sign and amount, of interfacial charge transfer is predicted by this scheme. Our findings provide guidelines for designing and controlling the functionalities in oxide nanostructures.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141705214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abdullah Al Mahfazur Rahman, Mohammad Tariqul Islam, Phumin Kirawanich, Badariah Bais, Haitham Alsaif, Abdulwadoud A. Maash, Ahasanul Hoque, Md. Moniruzzaman, Md. Shabiul Islam, Mohamed S. Soliman
This research paper demonstrates a metamaterial (MTM) based sensing technique to detect various blood samples by analyzing their dielectric properties. The performance of this MTM-based sensor is evaluated with the help of mimicked human blood samples that closely resemble the dielectric properties of actual human blood samples. Moreover, the ISM band frequency of 2.4 GHz is chosen as one of the reference resonance frequencies due to its various industrial and medical applications. The resonating patch is developed on the FR-4 substrate with a dimension of 10 × 20 mm2 that provides sharp reference resonances of 2.4 and 4.72 GHz for the spectra of the transmission coefficient with a good quality factor (Q-factor). The MTM sensor can detect the mimicked blood samples with a maximum frequency deviation of up to 650 MHz at 2.4 GHz and up to 850 MHz at 4.72 GHz, with maximum sensitivity of 0.917 and 0.707, respectively. The measured results using the prototype of the sensor support the simulation result with good agreement, indicating high sensing capability. Due to its high sensitivity, figure of merit (FoM), and frequency shifting with dielectric property changes in blood samples, the developed MTM-based sensor can be implemented effectively for quick sensing of infected blood samples and biomedical applications.
{"title":"A highly sensitive modified triple split ring metamaterial-based sensor for blood sample detection based on dielectric property alteration","authors":"Abdullah Al Mahfazur Rahman, Mohammad Tariqul Islam, Phumin Kirawanich, Badariah Bais, Haitham Alsaif, Abdulwadoud A. Maash, Ahasanul Hoque, Md. Moniruzzaman, Md. Shabiul Islam, Mohamed S. Soliman","doi":"10.1063/5.0218374","DOIUrl":"https://doi.org/10.1063/5.0218374","url":null,"abstract":"This research paper demonstrates a metamaterial (MTM) based sensing technique to detect various blood samples by analyzing their dielectric properties. The performance of this MTM-based sensor is evaluated with the help of mimicked human blood samples that closely resemble the dielectric properties of actual human blood samples. Moreover, the ISM band frequency of 2.4 GHz is chosen as one of the reference resonance frequencies due to its various industrial and medical applications. The resonating patch is developed on the FR-4 substrate with a dimension of 10 × 20 mm2 that provides sharp reference resonances of 2.4 and 4.72 GHz for the spectra of the transmission coefficient with a good quality factor (Q-factor). The MTM sensor can detect the mimicked blood samples with a maximum frequency deviation of up to 650 MHz at 2.4 GHz and up to 850 MHz at 4.72 GHz, with maximum sensitivity of 0.917 and 0.707, respectively. The measured results using the prototype of the sensor support the simulation result with good agreement, indicating high sensing capability. Due to its high sensitivity, figure of merit (FoM), and frequency shifting with dielectric property changes in blood samples, the developed MTM-based sensor can be implemented effectively for quick sensing of infected blood samples and biomedical applications.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Katja Kohopää, Alberto Ronzani, Robab Najafi Jabdaraghi, Arijit Bera, Mário Ribeiro, Dibyendu Hazra, Jorden Senior, Mika Prunnila, Joonas Govenius, Janne S. Lehtinen, Antti Kemppinen
We demonstrate ion irradiation by argon or gallium as a wafer-scale post-processing method to increase disorder in superconducting thin films. We study several widely used superconductors, both single-elements and compounds. We show that ion irradiation increases normal-state resistivity in all our films, which is expected to enable tuning their superconducting properties, for example, toward a higher kinetic inductance. We observe an increase in superconducting transition temperature for Al and MoSi and a decrease for Nb, NbN, and TiN. In MoSi, ion irradiation also improves the mixing of the two materials. We demonstrate the fabrication of an amorphous and homogeneous film of MoSi with uniform thickness, which is promising, for example, for superconducting nanowire single-photon detectors.
我们展示了氩或镓离子辐照作为晶圆级后处理方法来增加超导薄膜的无序性。我们研究了几种广泛使用的超导体，包括单元素和化合物。我们的研究表明，离子辐照会增加所有薄膜的正常态电阻率，这有望调整它们的超导特性，例如，使其具有更高的动能电感。我们观察到 Al 和 MoSi 的超导转变温度升高，而 Nb、NbN 和 TiN 的超导转变温度降低。在 MoSi 中，离子辐照也改善了两种材料的混合。我们展示了厚度均匀的无定形和均质 MoSi 薄膜的制备过程，这种薄膜有望用于超导纳米线单光子探测器等。
{"title":"Effect of ion irradiation on superconducting thin films","authors":"Katja Kohopää, Alberto Ronzani, Robab Najafi Jabdaraghi, Arijit Bera, Mário Ribeiro, Dibyendu Hazra, Jorden Senior, Mika Prunnila, Joonas Govenius, Janne S. Lehtinen, Antti Kemppinen","doi":"10.1063/5.0202851","DOIUrl":"https://doi.org/10.1063/5.0202851","url":null,"abstract":"We demonstrate ion irradiation by argon or gallium as a wafer-scale post-processing method to increase disorder in superconducting thin films. We study several widely used superconductors, both single-elements and compounds. We show that ion irradiation increases normal-state resistivity in all our films, which is expected to enable tuning their superconducting properties, for example, toward a higher kinetic inductance. We observe an increase in superconducting transition temperature for Al and MoSi and a decrease for Nb, NbN, and TiN. In MoSi, ion irradiation also improves the mixing of the two materials. We demonstrate the fabrication of an amorphous and homogeneous film of MoSi with uniform thickness, which is promising, for example, for superconducting nanowire single-photon detectors.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141532146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Takeshi Odagawa, Sota Yamamoto, Chaoliang Zhang, Kazuki Koyama, Jun Ishihara, Giacomo Mariani, Yoji Kunihashi, Haruki Sanada, Junsaku Nitta, Makoto Kohda
We investigate the excitonic species in WS2 monolayers transferred onto III–V semiconductor substrates with different surface treatments. When the III–V substrates were covered with amorphous native oxides, negatively charged excitons dominated the spectral weight in low-temperature near-resonance photoluminescence (PL) measurements. However, when the native oxides of the III–V substrates were reduced, neutral excitons began to dominate the spectral weight, indicating a reduction in the electron density in the WS2 monolayers. The removal of the native oxides enhanced the electron transfer from the WS2 monolayer to the III–V substrate. In addition, an additional shoulder-like PL feature appeared ∼50 meV below the emission of neutral excitons, which can be attributed to the emission of localized excitons. When the III–V substrate surface was passivated by sulfur after the reduction of the native oxides, neutral excitons still dominated the spectral weight. However, the low-energy PL shoulder disappeared again, suggesting the effective delocalization of excitons through substrate surface passivation. Surface engineering of the semiconductor substrates for two-dimensional (2D) materials can provide a novel approach to control the carrier density of the 2D materials, implement deterministic carrier localization or delocalization for the 2D materials, and facilitate the interlayer transfer of charge, spin, and valley currents. These findings open the avenue for novel device concepts and phenomena in mixed-dimensional semiconductor heterostructures.
{"title":"Enhanced interlayer electron transfer by surface treatments in mixed-dimensional van der Waals semiconductor heterostructures","authors":"Takeshi Odagawa, Sota Yamamoto, Chaoliang Zhang, Kazuki Koyama, Jun Ishihara, Giacomo Mariani, Yoji Kunihashi, Haruki Sanada, Junsaku Nitta, Makoto Kohda","doi":"10.1063/5.0214718","DOIUrl":"https://doi.org/10.1063/5.0214718","url":null,"abstract":"We investigate the excitonic species in WS2 monolayers transferred onto III–V semiconductor substrates with different surface treatments. When the III–V substrates were covered with amorphous native oxides, negatively charged excitons dominated the spectral weight in low-temperature near-resonance photoluminescence (PL) measurements. However, when the native oxides of the III–V substrates were reduced, neutral excitons began to dominate the spectral weight, indicating a reduction in the electron density in the WS2 monolayers. The removal of the native oxides enhanced the electron transfer from the WS2 monolayer to the III–V substrate. In addition, an additional shoulder-like PL feature appeared ∼50 meV below the emission of neutral excitons, which can be attributed to the emission of localized excitons. When the III–V substrate surface was passivated by sulfur after the reduction of the native oxides, neutral excitons still dominated the spectral weight. However, the low-energy PL shoulder disappeared again, suggesting the effective delocalization of excitons through substrate surface passivation. Surface engineering of the semiconductor substrates for two-dimensional (2D) materials can provide a novel approach to control the carrier density of the 2D materials, implement deterministic carrier localization or delocalization for the 2D materials, and facilitate the interlayer transfer of charge, spin, and valley currents. These findings open the avenue for novel device concepts and phenomena in mixed-dimensional semiconductor heterostructures.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Several papers reported the experimental phenomena of single crystal orthoferrite DyFeO3 samples: the sample magnetization increases with increasing temperature, under a constant low magnetic field along the easy magnetizing direction of the samples, and then reaches a maximum value. These phenomena are better explained using magnetic domain wall pinning at low temperatures and depinning at high temperatures, which were neglected in previous papers. In this article, we argue that the magnetic domain wall motion must be taken into consideration in order to explain these experimental phenomena. Based on an O 2p itinerant electron model, we discussed the role of the magnetic domain and the characteristics of cation magnetic moments in relevant single crystal materials.
多篇论文报道了单晶正铁氧体 DyFeO3 样品的实验现象：在沿样品易磁化方向的恒定低磁场下，样品磁化率随温度升高而增加，然后达到最大值。利用低温时的磁畴壁钉扎和高温时的磁畴壁脱钉现象可以更好地解释这些现象，而之前的论文忽略了这一点。在本文中，我们认为必须考虑磁畴壁运动才能解释这些实验现象。基于 O 2p 流动电子模型，我们讨论了磁畴的作用以及相关单晶材料中阳离子磁矩的特征。
{"title":"Magnetic domain wall pinning and depinning in DyFeO3 single crystal","authors":"Z. Z. Li, W. Qi, L. Ma, G. Tang, G. H. Wu","doi":"10.1063/5.0212820","DOIUrl":"https://doi.org/10.1063/5.0212820","url":null,"abstract":"Several papers reported the experimental phenomena of single crystal orthoferrite DyFeO3 samples: the sample magnetization increases with increasing temperature, under a constant low magnetic field along the easy magnetizing direction of the samples, and then reaches a maximum value. These phenomena are better explained using magnetic domain wall pinning at low temperatures and depinning at high temperatures, which were neglected in previous papers. In this article, we argue that the magnetic domain wall motion must be taken into consideration in order to explain these experimental phenomena. Based on an O 2p itinerant electron model, we discussed the role of the magnetic domain and the characteristics of cation magnetic moments in relevant single crystal materials.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141402172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We designed and fabricated our original laminated materials that simultaneously exhibited different properties: magneto-optical (MO), i.e., the transverse MO Kerr effects (T-MOKE) and surface-plasmon resonance (SPR). The material design was composed of dielectric, magnetic, and noble-metal layers. We selected the soft-magnetic FeSi thin film as a T-MOKE magnetic layer, while an Au thin film was chosen as a SPR-source layer, creating an FeSi-/Au-based “MO-SPR material.” Strong interactions between T-MOKE and SPR were demonstrated. When the material is irradiated with a laser beam of wavelength 660 nm, at the SPR angle to the material, θR, the highest T-MOKE value was attained. The T-MOKE was markedly enhanced at θR: ∼32 to ∼84 times higher compared with the FeSi single layer (reference). The T-MOKE was amplified by a strong interaction between MO activities and electromagnetic field distributions. The FeSi (5.0 nm)/Au (14.8 nm) specimen achieved the best signal-to-noise ratio (SNR). The sample was then tested for its sensing efficiency by measuring the T-MOKE using distilled water and a glucose solution, respectively: It was possible to distinguish between two different solutions. Our MO-SPR materials utilizing both magnetism and near-field light are thus sufficiently sensitive to be applicable as sensing materials. Furthermore, the polarity of the T-MOKE signal is flipped under the application of a small, external magnetic field owing to the soft magnetism of the FeSi T-MOKE layer. This is highly advantageous to create high-frequency AC-magnetic synchronized T-MOKE sensing systems with low-power consumption.
{"title":"Magneto-optical efficiencies combined with surface-plasmon resonance in FeSi/Au system","authors":"Yukiko Yasukawa, Masaki Itoh, Ryo Sugita, Haruki Yamane","doi":"10.1063/5.0194017","DOIUrl":"https://doi.org/10.1063/5.0194017","url":null,"abstract":"We designed and fabricated our original laminated materials that simultaneously exhibited different properties: magneto-optical (MO), i.e., the transverse MO Kerr effects (T-MOKE) and surface-plasmon resonance (SPR). The material design was composed of dielectric, magnetic, and noble-metal layers. We selected the soft-magnetic FeSi thin film as a T-MOKE magnetic layer, while an Au thin film was chosen as a SPR-source layer, creating an FeSi-/Au-based “MO-SPR material.” Strong interactions between T-MOKE and SPR were demonstrated. When the material is irradiated with a laser beam of wavelength 660 nm, at the SPR angle to the material, θR, the highest T-MOKE value was attained. The T-MOKE was markedly enhanced at θR: ∼32 to ∼84 times higher compared with the FeSi single layer (reference). The T-MOKE was amplified by a strong interaction between MO activities and electromagnetic field distributions. The FeSi (5.0 nm)/Au (14.8 nm) specimen achieved the best signal-to-noise ratio (SNR). The sample was then tested for its sensing efficiency by measuring the T-MOKE using distilled water and a glucose solution, respectively: It was possible to distinguish between two different solutions. Our MO-SPR materials utilizing both magnetism and near-field light are thus sufficiently sensitive to be applicable as sensing materials. Furthermore, the polarity of the T-MOKE signal is flipped under the application of a small, external magnetic field owing to the soft magnetism of the FeSi T-MOKE layer. This is highly advantageous to create high-frequency AC-magnetic synchronized T-MOKE sensing systems with low-power consumption.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141398397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. G. Stam, M. Gaowei, E. Echeverria, Kenneth Evans-Lutterodt, Jean Jordan-Sweet, T. Juffmann, S. Karkare, J. Maxson, S. J. van der Molen, C. Pennington, P. Saha, J. Smedley, R. M. Tromp
Ultra-flat, ultra-thin alkali antimonide photocathodes with high crystallinity can exhibit high quantum efficiency and low mean transverse energy of outgoing electrons, which are essential requirements for a variety of applications for photocathode materials. Here, we investigate the growth of Cs3Sb on graphene-coated 4H–SiC (Gr/4H–SiC), 3C–SiC, and Si3N4 substrates. Sb is deposited using pulsed laser deposition, while Cs is deposited thermally and simultaneously. We demonstrate, employing x-ray analysis and quantum efficiency measurements, that this growth method yields atomically smooth Cs3Sb photocathodes with a high quantum efficiency (>10%), even in the ultra-thin limit (<30 nm). For the Si3N4 substrate, film growth is shown to be polycrystalline, while films grown on Gr/4H–SiC show a high degree of ordering with signs of epitaxy.
{"title":"Growth of ultra-flat ultra-thin alkali antimonide photocathode films","authors":"W. G. Stam, M. Gaowei, E. Echeverria, Kenneth Evans-Lutterodt, Jean Jordan-Sweet, T. Juffmann, S. Karkare, J. Maxson, S. J. van der Molen, C. Pennington, P. Saha, J. Smedley, R. M. Tromp","doi":"10.1063/5.0213461","DOIUrl":"https://doi.org/10.1063/5.0213461","url":null,"abstract":"Ultra-flat, ultra-thin alkali antimonide photocathodes with high crystallinity can exhibit high quantum efficiency and low mean transverse energy of outgoing electrons, which are essential requirements for a variety of applications for photocathode materials. Here, we investigate the growth of Cs3Sb on graphene-coated 4H–SiC (Gr/4H–SiC), 3C–SiC, and Si3N4 substrates. Sb is deposited using pulsed laser deposition, while Cs is deposited thermally and simultaneously. We demonstrate, employing x-ray analysis and quantum efficiency measurements, that this growth method yields atomically smooth Cs3Sb photocathodes with a high quantum efficiency (>10%), even in the ultra-thin limit (<30 nm). For the Si3N4 substrate, film growth is shown to be polycrystalline, while films grown on Gr/4H–SiC show a high degree of ordering with signs of epitaxy.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141406947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Nagpal, E. Rauwel, Frédérique Ducroquet, Isabelle Gélard, P. Rauwel
This work reports on the fabrication of ZnO polymer-based hybrid ultraviolet (UV) photodiodes with a configuration of ITO/ZnO-nanorod/F8BT/PEDOT:PSS/Ag. The diode was fabricated by spin-coating p-type F8BT and PEDOT:PSS polymers on hydrothermally grown n-type ZnO nanorods. The growth of ZnO nanorods was carried out by varying seed layer alcohols, viz., methanol, ethanol, isopropanol, and aqueous ethanol (70% alcohol). These solvents influenced the nanorod diameter, surface coverage, and surface defects. Herein, we demonstrate that the uniformity and defects in ZnO nanorods govern the electrical properties, photoresponse, and figures of merit of the photodiodes. In particular, the photodiodes are evaluated on their rectification ratio, ideality factor (η), responsivity (R), external quantum efficiency (EQE), and response time (Tdecay). The photodiode fabricated with ZnO nanorods grown on the methanol seeding layer has demonstrated the best performance, owing to the uniform surface coverage of the nanorods. It also presented the highest rectification ratio of ∼640, a Tdecay of 108 s, a η of 2, an EQE of ∼2760%, and an R of ∼8.14 A/W at −2 V.
本研究报告介绍了基于氧化锌聚合物的混合紫外线（UV）光电二极管的制造过程，其配置为 ITO/氧化锌-纳米棒/F8BT/PEDOT:PSS/Ag。这种二极管是通过在水热法生长的 n 型氧化锌纳米棒上旋涂 p 型 F8BT 和 PEDOT:PSS 聚合物而制成的。氧化锌纳米棒的生长采用了不同的种子层醇，即甲醇、乙醇、异丙醇和乙醇水溶液（70% 酒精）。这些溶剂影响了纳米棒的直径、表面覆盖率和表面缺陷。在此，我们证明了氧化锌纳米棒的均匀性和缺陷会影响光电二极管的电学特性、光响应和性能指标。特别是，我们对光电二极管的整流比、理想系数 (η)、响应率 (R)、外部量子效率 (EQE) 和响应时间 (Tdecay) 进行了评估。用生长在甲醇播种层上的氧化锌纳米棒制造的光电二极管性能最佳，这是因为纳米棒表面覆盖均匀。它的整流比最高，达到 ∼640，Tdecay 为 108 秒，η 为 2，EQE 为 ∼2760%，-2 V 时的 R 为 ∼8.14 A/W。
{"title":"Fabrication and evaluation of figures of merit of ZnO polymer-based hybrid UV photodiodes","authors":"K. Nagpal, E. Rauwel, Frédérique Ducroquet, Isabelle Gélard, P. Rauwel","doi":"10.1063/5.0213681","DOIUrl":"https://doi.org/10.1063/5.0213681","url":null,"abstract":"This work reports on the fabrication of ZnO polymer-based hybrid ultraviolet (UV) photodiodes with a configuration of ITO/ZnO-nanorod/F8BT/PEDOT:PSS/Ag. The diode was fabricated by spin-coating p-type F8BT and PEDOT:PSS polymers on hydrothermally grown n-type ZnO nanorods. The growth of ZnO nanorods was carried out by varying seed layer alcohols, viz., methanol, ethanol, isopropanol, and aqueous ethanol (70% alcohol). These solvents influenced the nanorod diameter, surface coverage, and surface defects. Herein, we demonstrate that the uniformity and defects in ZnO nanorods govern the electrical properties, photoresponse, and figures of merit of the photodiodes. In particular, the photodiodes are evaluated on their rectification ratio, ideality factor (η), responsivity (R), external quantum efficiency (EQE), and response time (Tdecay). The photodiode fabricated with ZnO nanorods grown on the methanol seeding layer has demonstrated the best performance, owing to the uniform surface coverage of the nanorods. It also presented the highest rectification ratio of ∼640, a Tdecay of 108 s, a η of 2, an EQE of ∼2760%, and an R of ∼8.14 A/W at −2 V.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141403098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shengman Yu, Jingwei Shi, Tingting Sun, Zhigang Xie, Liyuan Sun
Antimicrobial photodynamic therapy has considerable promise in the fight against bacterial infections. The superior photophysical characteristics of porphyrins have made them effective photosensitizers in the field of phototherapy. Herein, the light-induced antimicrobial effects of three porphyrins with different substituents have been compared. 5,10,15,20-tetrakis(4-hydroxyphenyl) porphyrin (THPP) shows superior photosensitizing activity and antimicrobial ability under irradiation with green light. THPP can also inhibit and destroy mature Staphylococcus aureus biofilms under irradiation. This work provides a reference for the rational design of photosensitizers for application in antimicrobial photodynamic therapy.
{"title":"Light-induced antimicrobial activities of porphyrin derivatives as photosensitizers","authors":"Shengman Yu, Jingwei Shi, Tingting Sun, Zhigang Xie, Liyuan Sun","doi":"10.1063/5.0213923","DOIUrl":"https://doi.org/10.1063/5.0213923","url":null,"abstract":"Antimicrobial photodynamic therapy has considerable promise in the fight against bacterial infections. The superior photophysical characteristics of porphyrins have made them effective photosensitizers in the field of phototherapy. Herein, the light-induced antimicrobial effects of three porphyrins with different substituents have been compared. 5,10,15,20-tetrakis(4-hydroxyphenyl) porphyrin (THPP) shows superior photosensitizing activity and antimicrobial ability under irradiation with green light. THPP can also inhibit and destroy mature Staphylococcus aureus biofilms under irradiation. This work provides a reference for the rational design of photosensitizers for application in antimicrobial photodynamic therapy.","PeriodicalId":7985,"journal":{"name":"APL Materials","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141393292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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