Pub Date : 2024-07-31DOI: 10.1088/1674-4926/24020001
Aleksei Almaev, Alexander Tsymbalov, Bogdan Kushnarev, Vladimir Nikolaev, Alexei Pechnikov, Mikhail Scheglov and Andrei Chikiryaka
Detectors were developed for detecting irradiation in the short-wavelength ultraviolet (UVC) interval using high-quality single-crystalline α-Ga2O3 films with Pt interdigital contacts. The films of α-Ga2O3 were grown on planar sapphire substrates with c-plane orientation using halide vapor phase epitaxy. The spectral dependencies of the photo to dark current ratio, responsivity, external quantum efficiency and detectivity of the structures were investigated in the wavelength interval of 200−370 nm. The maximum of photo to dark current ratio, responsivity, external quantum efficiency, and detectivity of the structures were 1.16 × 104 arb. un., 30.6 A/W, 1.65 × 104%, and 6.95 × 1015 Hz0.5·cm/W at a wavelength of 230 nm and an applied voltage of 1 V. The high values of photoelectric properties were due to the internal enhancement of the photoresponse associated with strong hole trapping. The α-Ga2O3 film-based UVC detectors can function in self-powered operation mode due to the built-in electric field at the Pt/α-Ga2O3 interfaces. At a wavelength of 254 nm and zero applied voltage, the structures exhibit a responsivity of 0.13 mA/W and an external quantum efficiency of 6.2 × 10−2%. The UVC detectors based on the α-Ga2O3 films demonstrate high-speed performance with a rise time of 18 ms in self-powered mode.
{"title":"Self-powered UVC detectors based on α-Ga2O3 with enchanted speed performance","authors":"Aleksei Almaev, Alexander Tsymbalov, Bogdan Kushnarev, Vladimir Nikolaev, Alexei Pechnikov, Mikhail Scheglov and Andrei Chikiryaka","doi":"10.1088/1674-4926/24020001","DOIUrl":"https://doi.org/10.1088/1674-4926/24020001","url":null,"abstract":"Detectors were developed for detecting irradiation in the short-wavelength ultraviolet (UVC) interval using high-quality single-crystalline α-Ga2O3 films with Pt interdigital contacts. The films of α-Ga2O3 were grown on planar sapphire substrates with c-plane orientation using halide vapor phase epitaxy. The spectral dependencies of the photo to dark current ratio, responsivity, external quantum efficiency and detectivity of the structures were investigated in the wavelength interval of 200−370 nm. The maximum of photo to dark current ratio, responsivity, external quantum efficiency, and detectivity of the structures were 1.16 × 104 arb. un., 30.6 A/W, 1.65 × 104%, and 6.95 × 1015 Hz0.5·cm/W at a wavelength of 230 nm and an applied voltage of 1 V. The high values of photoelectric properties were due to the internal enhancement of the photoresponse associated with strong hole trapping. The α-Ga2O3 film-based UVC detectors can function in self-powered operation mode due to the built-in electric field at the Pt/α-Ga2O3 interfaces. At a wavelength of 254 nm and zero applied voltage, the structures exhibit a responsivity of 0.13 mA/W and an external quantum efficiency of 6.2 × 10−2%. The UVC detectors based on the α-Ga2O3 films demonstrate high-speed performance with a rise time of 18 ms in self-powered mode.","PeriodicalId":17038,"journal":{"name":"Journal of Semiconductors","volume":"9 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1088/1674-4926/24010029
Ziwei Hu, Jiafei Yao, Ang Li, Qi Sun, Man Li, Kemeng Yang, Jun Zhang, Jing Chen, Maolin Zhang and Yufeng Guo
Silicon carbide (SiC), as a third-generation semiconductor material, possesses exceptional material properties that significantly enhance the performance of power devices. The SiC lateral double-diffused metal–oxide–semiconductor (LDMOS) power devices have undergone continuous optimization, resulting in an increase in breakdown voltage (BV) and ultra-low specific on-resistance (Ron,sp). This paper has summarized the structural optimizations and experimental progress of SiC LDMOS power devices, including the trench-gate technology, reduced surface field (RESURF) technology, doping technology, junction termination techniques and so on. The paper is aimed at enhancing the understanding of the operational mechanisms and providing guidelines for the further development of SiC LDMOS power devices.
碳化硅（SiC）作为第三代半导体材料，具有优异的材料特性，可显著提高功率器件的性能。碳化硅侧向双扩散金属氧化物半导体（LDMOS）功率器件经过不断优化，实现了击穿电压（BV）的提高和超低比导通电阻（Ron,sp）。本文总结了 SiC LDMOS 功率器件的结构优化和实验进展，包括沟槽栅极技术、减小表面场（RESURF）技术、掺杂技术、结端技术等。本文旨在加深对工作机制的理解，并为进一步开发 SiC LDMOS 功率器件提供指导。
{"title":"Review of the SiC LDMOS power device","authors":"Ziwei Hu, Jiafei Yao, Ang Li, Qi Sun, Man Li, Kemeng Yang, Jun Zhang, Jing Chen, Maolin Zhang and Yufeng Guo","doi":"10.1088/1674-4926/24010029","DOIUrl":"https://doi.org/10.1088/1674-4926/24010029","url":null,"abstract":"Silicon carbide (SiC), as a third-generation semiconductor material, possesses exceptional material properties that significantly enhance the performance of power devices. The SiC lateral double-diffused metal–oxide–semiconductor (LDMOS) power devices have undergone continuous optimization, resulting in an increase in breakdown voltage (BV) and ultra-low specific on-resistance (Ron,sp). This paper has summarized the structural optimizations and experimental progress of SiC LDMOS power devices, including the trench-gate technology, reduced surface field (RESURF) technology, doping technology, junction termination techniques and so on. The paper is aimed at enhancing the understanding of the operational mechanisms and providing guidelines for the further development of SiC LDMOS power devices.","PeriodicalId":17038,"journal":{"name":"Journal of Semiconductors","volume":"41 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1088/1674-4926/24040008
Danrui Wan, Jianping Zhou, Guoyun Meng, Ning Su, Dongdong Zhang, Lian Duan and Junqiao Ding
Boron−nitrogen doped multiple resonance (BN-MR) emitters, characterized by B−N covalent bonds, offer distinctive advantages as pivotal building blocks for facile access to novel MR emitters featuring narrowband spectra and high efficiency. However, there remains a scarcity of exploration concerning synthetic methods and structural derivations to expand the library of novel BN-MR emitters. Herein, we present the synthesis of a BN-MR emitter, tCz[B−N]N, through a one-pot borylation reaction directed by the amine group, achieving an impressive yield of 94%. The emitter is decorated by incorporating two 3,6-di-t-butylcarbazole (tCz) units into a B−N covalent bond doped BN-MR parent molecule via para-C−π−D and para-N−π−D conjugations. This peripheral decoration strategy enhances the reverse intersystem crossing process and shifts the emission band towards the pure green region, peaking at 526 nm with a narrowband full-width at half maximum (FWHM) of 41 nm. Consequently, organic light emitting diodes (OLEDs) employing this emitter achieved a maximum external quantum efficiency (EQEmax) value of 27.7%, with minimal efficiency roll-off. Even at a practical luminance of 1000 cd∙m−2, the device maintains a high EQE value of 24.6%.
{"title":"Peripheral carbazole units-decorated MR emitter containing B−N covalent bond for highly efficient green OLEDs with low roll-off","authors":"Danrui Wan, Jianping Zhou, Guoyun Meng, Ning Su, Dongdong Zhang, Lian Duan and Junqiao Ding","doi":"10.1088/1674-4926/24040008","DOIUrl":"https://doi.org/10.1088/1674-4926/24040008","url":null,"abstract":"Boron−nitrogen doped multiple resonance (BN-MR) emitters, characterized by B−N covalent bonds, offer distinctive advantages as pivotal building blocks for facile access to novel MR emitters featuring narrowband spectra and high efficiency. However, there remains a scarcity of exploration concerning synthetic methods and structural derivations to expand the library of novel BN-MR emitters. Herein, we present the synthesis of a BN-MR emitter, tCz[B−N]N, through a one-pot borylation reaction directed by the amine group, achieving an impressive yield of 94%. The emitter is decorated by incorporating two 3,6-di-t-butylcarbazole (tCz) units into a B−N covalent bond doped BN-MR parent molecule via para-C−π−D and para-N−π−D conjugations. This peripheral decoration strategy enhances the reverse intersystem crossing process and shifts the emission band towards the pure green region, peaking at 526 nm with a narrowband full-width at half maximum (FWHM) of 41 nm. Consequently, organic light emitting diodes (OLEDs) employing this emitter achieved a maximum external quantum efficiency (EQEmax) value of 27.7%, with minimal efficiency roll-off. Even at a practical luminance of 1000 cd∙m−2, the device maintains a high EQE value of 24.6%.","PeriodicalId":17038,"journal":{"name":"Journal of Semiconductors","volume":"86 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1088/1674-4926/24030038
Xiyu Hou, Lianjun Wen, Fengyue He, Ran Zhuo, Lei Liu, Hailong Wang, Qing Zhong, Dong Pan and Jianhua Zhao
Semiconductor quantum dots are promising candidates for preparing high-performance single photon sources. A basic requirement for this application is realizing the controlled growth of high-quality semiconductor quantum dots. Here, we report the growth of embedded GaAs1−xSbx quantum dots in GaAs nanowires by molecular-beam epitaxy. It is found that the size of the GaAs1−xSbx quantum dot can be well-defined by the GaAs nanowire. Energy dispersive spectroscopy analyses show that the antimony content x can be up to 0.36 by tuning the growth temperature. All GaAs1−xSbx quantum dots exhibit a pure zinc-blende phase. In addition, we have developed a new technology to grow GaAs passivation layers on the sidewalls of the GaAs1−xSbx quantum dots. Different from the traditional growth process of the passivation layer, GaAs passivation layers can be grown simultaneously with the growth of the embedded GaAs1−xSbx quantum dots. The spontaneous GaAs passivation layer shows a pure zinc-blende phase due to the strict epitaxial relationship between the quantum dot and the passivation layer. The successful fabrication of embedded high-quality GaAs1−xSbx quantum dots lays the foundation for the realization of GaAs1−xSbx-based single photon sources.
{"title":"Embedded high-quality ternary GaAs1−x Sb x quantum dots in GaAs nanowires by molecular-beam epitaxy","authors":"Xiyu Hou, Lianjun Wen, Fengyue He, Ran Zhuo, Lei Liu, Hailong Wang, Qing Zhong, Dong Pan and Jianhua Zhao","doi":"10.1088/1674-4926/24030038","DOIUrl":"https://doi.org/10.1088/1674-4926/24030038","url":null,"abstract":"Semiconductor quantum dots are promising candidates for preparing high-performance single photon sources. A basic requirement for this application is realizing the controlled growth of high-quality semiconductor quantum dots. Here, we report the growth of embedded GaAs1−xSbx quantum dots in GaAs nanowires by molecular-beam epitaxy. It is found that the size of the GaAs1−xSbx quantum dot can be well-defined by the GaAs nanowire. Energy dispersive spectroscopy analyses show that the antimony content x can be up to 0.36 by tuning the growth temperature. All GaAs1−xSbx quantum dots exhibit a pure zinc-blende phase. In addition, we have developed a new technology to grow GaAs passivation layers on the sidewalls of the GaAs1−xSbx quantum dots. Different from the traditional growth process of the passivation layer, GaAs passivation layers can be grown simultaneously with the growth of the embedded GaAs1−xSbx quantum dots. The spontaneous GaAs passivation layer shows a pure zinc-blende phase due to the strict epitaxial relationship between the quantum dot and the passivation layer. The successful fabrication of embedded high-quality GaAs1−xSbx quantum dots lays the foundation for the realization of GaAs1−xSbx-based single photon sources.","PeriodicalId":17038,"journal":{"name":"Journal of Semiconductors","volume":"193 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1088/1674-4926/24010017
Siyi Huang, Masao Ikeda, Feng Zhang, Minglong Zhang, Jianjun Zhu, Shuming Zhang and Jianping Liu
Relationship between the hole concentration at room temperature and the Mg doping concentration in p-GaN grown by MOCVD after sufficient annealing was studied in this paper. Different annealing conditions were applied to obtain sufficient activation for p-GaN samples with different Mg doping ranges. Hole concentration, resistivity and mobility were characterized by room-temperature Hall measurements. The Mg doping concentration and the residual impurities such as H, C, O and Si were measured by secondary ion mass spectroscopy, confirming negligible compensations by the impurities. The hole concentration, resistivity and mobility data are presented as a function of Mg concentration, and are compared with literature data. The appropriate curve relating the Mg doping concentration to the hole concentration is derived using a charge neutrality equation and the ionized-acceptor-density [ ] (cm−3) dependent ionization energy of Mg acceptor was determined as = 184 − 2.66 × 10−5 × [ ]1/3 meV.
{"title":"Achievable hole concentration at room temperature as a function of Mg concentration for MOCVD-grown p-GaN after sufficient annealing","authors":"Siyi Huang, Masao Ikeda, Feng Zhang, Minglong Zhang, Jianjun Zhu, Shuming Zhang and Jianping Liu","doi":"10.1088/1674-4926/24010017","DOIUrl":"https://doi.org/10.1088/1674-4926/24010017","url":null,"abstract":"Relationship between the hole concentration at room temperature and the Mg doping concentration in p-GaN grown by MOCVD after sufficient annealing was studied in this paper. Different annealing conditions were applied to obtain sufficient activation for p-GaN samples with different Mg doping ranges. Hole concentration, resistivity and mobility were characterized by room-temperature Hall measurements. The Mg doping concentration and the residual impurities such as H, C, O and Si were measured by secondary ion mass spectroscopy, confirming negligible compensations by the impurities. The hole concentration, resistivity and mobility data are presented as a function of Mg concentration, and are compared with literature data. The appropriate curve relating the Mg doping concentration to the hole concentration is derived using a charge neutrality equation and the ionized-acceptor-density [ ] (cm−3) dependent ionization energy of Mg acceptor was determined as = 184 − 2.66 × 10−5 × [ ]1/3 meV.","PeriodicalId":17038,"journal":{"name":"Journal of Semiconductors","volume":"27 Pt 4 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1088/1674-4926/24020018
Kun Wang, Wenxuan Lai, Zhenyi Ni, Deren Yang and Xiaodong Pi
Ratiometric fluorescent detection of iron(Ⅲ) (Fe3+) offers inherent self-calibration and contactless analytic capabilities. However, realizing a dual-emission near-infrared (NIR) nanosensor with a low limit of detection (LOD) is rather challenging. In this work, we report the synthesis of water-dispersible erbium-hyperdoped silicon quantum dots (Si QDs:Er), which emit NIR light at the wavelengths of 810 and 1540 nm. A dual-emission NIR nanosensor based on water-dispersible Si QDs:Er enables ratiometric Fe3+ detection with a very low LOD (0.06 μM). The effects of pH, recyclability, and the interplay between static and dynamic quenching mechanisms for Fe3+ detection have been systematically studied. In addition, we demonstrate that the nanosensor may be used to construct a sequential logic circuit with memory functions.
{"title":"A highly sensitive ratiometric near-infrared nanosensor based on erbium-hyperdoped silicon quantum dots for iron(Ⅲ) detection","authors":"Kun Wang, Wenxuan Lai, Zhenyi Ni, Deren Yang and Xiaodong Pi","doi":"10.1088/1674-4926/24020018","DOIUrl":"https://doi.org/10.1088/1674-4926/24020018","url":null,"abstract":"Ratiometric fluorescent detection of iron(Ⅲ) (Fe3+) offers inherent self-calibration and contactless analytic capabilities. However, realizing a dual-emission near-infrared (NIR) nanosensor with a low limit of detection (LOD) is rather challenging. In this work, we report the synthesis of water-dispersible erbium-hyperdoped silicon quantum dots (Si QDs:Er), which emit NIR light at the wavelengths of 810 and 1540 nm. A dual-emission NIR nanosensor based on water-dispersible Si QDs:Er enables ratiometric Fe3+ detection with a very low LOD (0.06 μM). The effects of pH, recyclability, and the interplay between static and dynamic quenching mechanisms for Fe3+ detection have been systematically studied. In addition, we demonstrate that the nanosensor may be used to construct a sequential logic circuit with memory functions.","PeriodicalId":17038,"journal":{"name":"Journal of Semiconductors","volume":"39 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1088/1674-4926/24030019
Na Tian, Zhe Wang, Kai Ma, Xu Yang, Nan Qi, Jian Liu, Nanjian Wu, Runjiang Dou and Liyuan Liu
This paper presents a design of single photon avalanche diode (SPAD) light detection and ranging (LiDAR) sensor with 128 × 128 pixels and 128 column-parallel time-to-analog-merged-analog-to-digital converts (TA-ADCs). Unlike the conventional TAC-based SPAD LiDAR sensor, in which the TAC and ADC are separately implemented, we propose to merge the TAC and ADC by sharing their capacitors, thus avoiding the analog readout noise of TAC’s output buffer, improving the conversion rate, and reducing chip area. The reverse start-stop logic is employed to reduce the power of the TA-ADC. Fabricated in a 180 nm CMOS process, our prototype sensor exhibits a timing resolution of 25 ps, a DNL of +0.30/−0.77 LSB, an INL of +1.41/−2.20 LSB, and a total power consumption of 190 mW. A flash LiDAR system based on this sensor demonstrates the function of 2D/3D imaging with 128 × 128 resolution, 25 kHz inter-frame rate, and sub-centimeter ranging precision.
{"title":"A 128 × 128 SPAD LiDAR sensor with column-parallel 25 ps resolution TA-ADCs","authors":"Na Tian, Zhe Wang, Kai Ma, Xu Yang, Nan Qi, Jian Liu, Nanjian Wu, Runjiang Dou and Liyuan Liu","doi":"10.1088/1674-4926/24030019","DOIUrl":"https://doi.org/10.1088/1674-4926/24030019","url":null,"abstract":"This paper presents a design of single photon avalanche diode (SPAD) light detection and ranging (LiDAR) sensor with 128 × 128 pixels and 128 column-parallel time-to-analog-merged-analog-to-digital converts (TA-ADCs). Unlike the conventional TAC-based SPAD LiDAR sensor, in which the TAC and ADC are separately implemented, we propose to merge the TAC and ADC by sharing their capacitors, thus avoiding the analog readout noise of TAC’s output buffer, improving the conversion rate, and reducing chip area. The reverse start-stop logic is employed to reduce the power of the TA-ADC. Fabricated in a 180 nm CMOS process, our prototype sensor exhibits a timing resolution of 25 ps, a DNL of +0.30/−0.77 LSB, an INL of +1.41/−2.20 LSB, and a total power consumption of 190 mW. A flash LiDAR system based on this sensor demonstrates the function of 2D/3D imaging with 128 × 128 resolution, 25 kHz inter-frame rate, and sub-centimeter ranging precision.","PeriodicalId":17038,"journal":{"name":"Journal of Semiconductors","volume":"27 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-01DOI: 10.1088/1674-4926/45/2/022101
Karolis Stašys, Andrejus Geižutis, Jan Devenson
We introduce a novel method to create mid-infrared (MIR) thermal emitters using fully epitaxial, metal-free structures. Through the strategic use of epsilon-near-zero (ENZ) thin films in InAs layers, we achieve a narrow-band, wide-angle, and p-polarized thermal emission spectra. This approach, employing molecular beam epitaxy, circumvents the complexities associated with current layered structures and yields temperature-resistant emission wavelengths. Our findings contribute a promising route towards simpler, more efficient MIR optoelectronic devices.
我们介绍了一种利用全外延、无金属结构制造中红外（MIR）热发射器的新方法。通过在 InAs 层中战略性地使用ε-近零（ENZ）薄膜，我们实现了窄带、广角和 p 偏振热发射光谱。这种采用分子束外延的方法避免了当前分层结构的复杂性，并产生了耐高温的发射波长。我们的研究成果为实现更简单、更高效的近红外光电器件开辟了一条前景广阔的道路。
{"title":"Enhanced thermal emission from metal-free, fully epitaxial structures with epsilon-near-zero InAs layers","authors":"Karolis Stašys, Andrejus Geižutis, Jan Devenson","doi":"10.1088/1674-4926/45/2/022101","DOIUrl":"https://doi.org/10.1088/1674-4926/45/2/022101","url":null,"abstract":"We introduce a novel method to create mid-infrared (MIR) thermal emitters using fully epitaxial, metal-free structures. Through the strategic use of epsilon-near-zero (ENZ) thin films in InAs layers, we achieve a narrow-band, wide-angle, and p-polarized thermal emission spectra. This approach, employing molecular beam epitaxy, circumvents the complexities associated with current layered structures and yields temperature-resistant emission wavelengths. Our findings contribute a promising route towards simpler, more efficient MIR optoelectronic devices.","PeriodicalId":17038,"journal":{"name":"Journal of Semiconductors","volume":"12 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139761811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-01DOI: 10.1088/1674-4926/45/2/022301
Hengbin Ding, Xiaoshi Li, Tianhang Li, Xiaoyong Zhao, He Tian
Phase-change material (PCM) is widely used in thermal management due to their unique thermal behavior. However, related research in thermal rectifier is mainly focused on exploring the principles at the fundamental device level, which results in a gap to real applications. Here, we propose a controllable thermal rectification design towards building applications through the direct adhesion of composite thermal rectification material (TRM) based on PCM and reduced graphene oxide (rGO) aerogel to ordinary concrete walls (CWs). The design is evaluated in detail by combining experiments and finite element analysis. It is found that, TRM can regulate the temperature difference on both sides of the TRM/CWs system by thermal rectification. The difference in two directions reaches to 13.8 K at the heat flow of 80 W/m2. In addition, the larger the change of thermal conductivity before and after phase change of TRM is, the more effective it is for regulating temperature difference in two directions. The stated technology has a wide range of applications for the thermal energy control in buildings with specific temperature requirements.
{"title":"Controllable thermal rectification design for buildings based on phase change composites","authors":"Hengbin Ding, Xiaoshi Li, Tianhang Li, Xiaoyong Zhao, He Tian","doi":"10.1088/1674-4926/45/2/022301","DOIUrl":"https://doi.org/10.1088/1674-4926/45/2/022301","url":null,"abstract":"Phase-change material (PCM) is widely used in thermal management due to their unique thermal behavior. However, related research in thermal rectifier is mainly focused on exploring the principles at the fundamental device level, which results in a gap to real applications. Here, we propose a controllable thermal rectification design towards building applications through the direct adhesion of composite thermal rectification material (TRM) based on PCM and reduced graphene oxide (rGO) aerogel to ordinary concrete walls (CWs). The design is evaluated in detail by combining experiments and finite element analysis. It is found that, TRM can regulate the temperature difference on both sides of the TRM/CWs system by thermal rectification. The difference in two directions reaches to 13.8 K at the heat flow of 80 W/m<sup>2</sup>. In addition, the larger the change of thermal conductivity before and after phase change of TRM is, the more effective it is for regulating temperature difference in two directions. The stated technology has a wide range of applications for the thermal energy control in buildings with specific temperature requirements.","PeriodicalId":17038,"journal":{"name":"Journal of Semiconductors","volume":"42 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139761890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-01DOI: 10.1088/1674-4926/45/2/021501
Jiaming Wang, Fujun Xu, Lisheng Zhang, Jing Lang, Xuzhou Fang, Ziyao Zhang, Xueqi Guo, Chen Ji, Chengzhi Ji, Fuyun Tan, Xuelin Yang, Xiangning Kang, Zhixin Qin, Ning Tang, Xinqiang Wang, Weikun Ge, Bo Shen
The development of semiconductors is always accompanied by the progress in controllable doping techniques. Taking AlGaN-based ultraviolet (UV) emitters as an example, despite a peak wall-plug efficiency of 15.3% at the wavelength of 275 nm, there is still a huge gap in comparison with GaN-based visible light-emitting diodes (LEDs), mainly attributed to the inefficient doping of AlGaN with increase of the Al composition. First, p-doping of Al-rich AlGaN is a long-standing challenge and the low hole concentration seriously restricts the carrier injection efficiency. Although p-GaN cladding layers are widely adopted as a compromise, the high injection barrier of holes as well as the inevitable loss of light extraction cannot be neglected. While in terms of n-doping the main issue is the degradation of the electrical property when the Al composition exceeds 80%, resulting in a low electrical efficiency in sub-250 nm UV-LEDs. This review summarizes the recent advances and outlines the major challenges in the efficient doping of Al-rich AlGaN, meanwhile the corresponding approaches pursued to overcome the doping issues are discussed in detail.
半导体的发展始终伴随着可控掺杂技术的进步。以氮化镓基紫外线（UV）发射器为例，尽管在波长为 275 纳米时的峰值插壁效率达到了 15.3%，但与氮化镓基可见光发光二极管（LED）相比仍存在巨大差距，这主要归因于氮化镓的掺杂效率随铝成分的增加而降低。首先，富铝 AlGaN 的 p 掺杂是一个长期存在的难题，低空穴浓度严重限制了载流子注入效率。虽然 p-GaN 包层作为一种折中方案被广泛采用，但空穴的高注入势垒以及不可避免的光提取损失不容忽视。而在 n 掺杂方面，主要问题是当铝的成分超过 80% 时，电性能会下降，从而导致 250 nm 以下紫外发光二极管的电效率较低。本综述总结了最近的研究进展，概述了高效掺杂富铝氮化铝的主要挑战，同时详细讨论了克服掺杂问题的相应方法。
{"title":"Progress in efficient doping of Al-rich AlGaN","authors":"Jiaming Wang, Fujun Xu, Lisheng Zhang, Jing Lang, Xuzhou Fang, Ziyao Zhang, Xueqi Guo, Chen Ji, Chengzhi Ji, Fuyun Tan, Xuelin Yang, Xiangning Kang, Zhixin Qin, Ning Tang, Xinqiang Wang, Weikun Ge, Bo Shen","doi":"10.1088/1674-4926/45/2/021501","DOIUrl":"https://doi.org/10.1088/1674-4926/45/2/021501","url":null,"abstract":"The development of semiconductors is always accompanied by the progress in controllable doping techniques. Taking AlGaN-based ultraviolet (UV) emitters as an example, despite a peak wall-plug efficiency of 15.3% at the wavelength of 275 nm, there is still a huge gap in comparison with GaN-based visible light-emitting diodes (LEDs), mainly attributed to the inefficient doping of AlGaN with increase of the Al composition. First, p-doping of Al-rich AlGaN is a long-standing challenge and the low hole concentration seriously restricts the carrier injection efficiency. Although p-GaN cladding layers are widely adopted as a compromise, the high injection barrier of holes as well as the inevitable loss of light extraction cannot be neglected. While in terms of n-doping the main issue is the degradation of the electrical property when the Al composition exceeds 80%, resulting in a low electrical efficiency in sub-250 nm UV-LEDs. This review summarizes the recent advances and outlines the major challenges in the efficient doping of Al-rich AlGaN, meanwhile the corresponding approaches pursued to overcome the doping issues are discussed in detail.","PeriodicalId":17038,"journal":{"name":"Journal of Semiconductors","volume":"60 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139761807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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