Article
Chemistry, Multidisciplinary
Jin-Ji Dai, Thi Thu Mai, Ssu-Kuan Wu, Jing-Rong Peng, Cheng-Wei Liu, Hua-Chiang Wen, Wu-Ching Chou, Han-Chieh Ho, Wei-Fan Wang
Summary: The study found that Mg doping can effectively enhance the activation efficiency and hole concentration in p-GaN/AlGaN structures. By using an AlN interlayer, the activation rate can be further improved and the diffusion of Mg atoms can be effectively suppressed.
Article
Chemistry, Physical
Aadil Waseem, Muhammad Ali Johar, Mostafa Afifi Hassan, Indrajit Bagal, Ameer Abdullah, Jun-Seok Ha, June Key Lee, Sang-Wan Ryu
Summary: The proposed flexible piezoelectric pressure sensor (PEPS) utilizes p-n junction coaxial GaN nanowires to achieve self-power generation, high power density, energy storage, and stable voltage response to both dynamic and static pressure signals.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Physics, Applied
Zhenghao Chen, Xuelin Yang, Danshuo Liu, Zidong Cai, Huayang Huang, Liwen Sang, Fujun Xu, Xinqiang Wang, Weikun Ge, Bo Shen
Summary: Controlling the partial pressure of NH3 is crucial for reducing the carbon impurity in GaN drift layers, leading to high mobility GaN vertical power devices. The study shows that the NH3 partial pressure is the key parameter in determining the carbon concentration. By increasing the NH3 partial pressure, the surface N vacancy concentration decreases, resulting in lower carbon incorporation efficiency. This approach effectively lowers the carbon concentration to 1.7 x 10(15)/cm(3) and achieves a record high electron mobility of 1227 cm(2)/Vs at room temperature, paving the way for high performance kV-class GaN vertical power devices on Si substrates.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Ying Zhao, Shengrui Xu, Hongchang Tao, Yachao Zhang, Chunfu Zhang, Lansheng Feng, Ruoshi Peng, Xiaomeng Fan, Jinjuan Du, Jincheng Zhang, Yue Hao
Summary: The study proposed a method of combining AlGaN/GaN superlattices and Mg delta doping to achieve a high conductivity p-type GaN layer. Experimental results showed that the novel doping technique significantly improved p-conductivity and enhanced the light output power and external quantum efficiency of the fabricated green-yellow light-emitting diodes.
Article
Nanoscience & Nanotechnology
Kwang Jae Lee, Yusuke Nakazato, Jaeyi Chun, Xinyi Wen, Chuanzhe Meng, Rohith Soman, Maliha Noshin, Srabanti Chowdhury
Summary: This study presents experimental evidence for the use of nanoporous GaN (NP GaN) as a compensation layer to prevent the diffusion of magnesium (Mg) from p-type gallium nitride (p-GaN). Additionally, the study reveals the significant impact of NP GaN on the electron concentration of AlGaN/GaN structures.
Article
Materials Science, Multidisciplinary
Kwang Jae Lee, Xinyi Wen, Yusuke Nakazato, Jaeyi Chun, Maliha Noshin, Chuanzhe Meng, Srabanti Chowdhury
Summary: This study systematically investigated the regrowth of low-temperature GaN (LT-GaN) layer on p-GaN to suppress the diffusion of Mg, enabling the fabrication of high-electron-mobility transistors (HEMTs) with high 2D electron gas (2DEG) density. The fabricated HEMTs with 100 nm-thick LT-GaN demonstrated a high drain current density and low on-state resistance.
FRONTIERS IN MATERIALS
(2023)
Article
Physics, Applied
Yuxuan Zhang, Vijay Gopal Thirupakuzi Vangipuram, Kaitian Zhang, Hongping Zhao
Summary: This study demonstrates the reduction of carbon impurities in metalorganic chemical vapor deposition (MOCVD) grown gallium nitride (GaN) using laser-assisted MOCVD (LA-MOCVD) technique. The incorporation of carbon is effectively suppressed in LA-MOCVD under different growth rate regimes. A theoretical model explains the mechanism of carbon incorporation and suggests that higher power LA-MOCVD and freestanding GaN substrates with larger off-cut angles can further reduce carbon impurity levels.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Shun Lu, Manato Deki, Jia Wang, Kazuki Ohnishi, Yuto Ando, Takeru Kumabe, Hirotaka Watanabe, Shugo Nitta, Yoshio Honda, Hiroshi Amano
Summary: The study demonstrated a fabrication process for Ohmic contact on low-doping-density p-type GaN with nitrogen-annealed Mg, achieving reduced contact resistance and a localized contact layer. The mechanism underlying the reduced contact resistance, involving mutual diffusion of Ga and Mg atoms on the interface, was studied using various techniques such as scanning transmission electron microscopy.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Condensed Matter
Yang Wang, Bin Duan, Gaoqiang Deng, Ye Yu, Yunfei Niu, Jiaqi Yu, Haotian Ma, Zhifeng Shi, Baolin Zhang, Yuantao Zhang
Summary: In this study, blue-green InGaN/GaN multiple quantum wells were grown on SiC substrates by metal-organic chemical vapor deposition, and the influence of growth pressure on their structural and optical properties was investigated. It was found that increasing growth pressure nearly doubles the indium content in the MQWs and leads to distinct temperature-dependent optical behaviors. Furthermore, growth pressure significantly affects the structural characteristics of the MQWs, influencing surface morphology and defect density.
SUPERLATTICES AND MICROSTRUCTURES
(2021)
Article
Physics, Applied
Yuta Itoh, Shun Lu, Hirotaka Watanabe, Manato Deki, Shugo Nitta, Yoshio Honda, Atsushi Tanaka, Hiroshi Amano
Summary: The research evaluated the diffusion of Mg from GaN/Mg mixture into GaN. It was found that the diffusion depth of Mg increased with temperature, while the Mg concentration remained constant. The Mg-diffused GaN samples exhibited p-type conductivity with a high hole mobility.
APPLIED PHYSICS EXPRESS
(2022)
Article
Chemistry, Physical
Jin-Ji Dai, Thi Thu Mai, Umeshwar Reddy Nallasani, Shao-Chien Chang, Hsin- Hsiao, Ssu-Kuan Wu, Cheng-Wei Liu, Hua-Chiang Wen, Wu-Ching Chou, Chieh-Piao Wang, Luc Huy Hoang
Summary: In this study, HEMT structures with heavily Fe-doped GaN buffer layers were fabricated on Si (111) substrates by MOCVD. The heavily Fe-doped buffer layer showed 3D growth mode, which effectively reduced threading dislocations and vertical leakage current.
Article
Engineering, Electrical & Electronic
Guangnan Zhou, Fanming Zeng, Rongyu Gao, Qing Wang, Kai Cheng, Lingqi Li, Peng Xiang, Fangzhou Du, Guangrui Xia, Hongyu Yu
Summary: We have presented a novel p-GaN gate HEMT structure with reduced hole concentration near the Schottky interface using doping engineering in metal-organic chemical vapor deposition (MOCVD). By incorporating an unintentionally doped GaN (u-GaN) layer, the gate leakage current is suppressed and the gate breakdown voltage is increased without affecting the threshold voltage and on-resistance. Time-dependent gate breakdown measurements show that the maximum gate drive voltage can be increased for a ten-year lifetime with a 1% gate failure rate, effectively expanding the operating voltage margin of p-GaN gate HEMTs without the need for additional process steps.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Nanoscience & Nanotechnology
Hoe-Min Kwak, Jongil Kim, Je-Sung Lee, Jeongwoon Kim, Jaeyoung Baik, Soo-Young Choi, Sunwoo Shin, Jin-Soo Kim, Seung-Hyun Mun, Kyung-Pil Kim, Sang Ho Oh, Dong-Seon Lee
Summary: This study presents an approach for growing and exfoliating GaN on 2D material/GaN templates. The key is to protect the integrity of the 2D material in high-temperature growth conditions. With effective protection, GaN can endure high temperatures and still be exfoliated.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Ceramics
Kai Chen, Yachao Zhang, Jincheng Zhang, Xing Wang, Yixin Yao, Jinbang Ma, Yue Hao
Summary: By analyzing the growth modes of GaN films on AlN buffer layers with different thicknesses, a new growth model of GaN on AlN buffer was proposed in this study. Under optimal conditions, AlGaN/GaN/AlN heterostructures showed excellent performance.
CERAMICS INTERNATIONAL
(2022)
Article
Engineering, Electrical & Electronic
Hadi Ebrahimi-Darkhaneh, Mahsa Shekarnoush, Josefina Arellano-Jimenez, Rodolfo Rodriguez, Luigi Colombo, Manuel Quevedo-Lopez, Sanjay K. Banerjee
Summary: Epitaxial growth and characterization of Mg-doped Ga2O3 thin films on sapphire substrates using pulsed laser deposition were investigated. The films exhibited p-type semiconducting behavior and an increased band gap compared to pure Ga2O3, making them suitable for applications in ultraviolet photodetectors and power electronic devices.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Crystallography
Jianzheng Hu, Long Yan, Ning Zhou, Yao Chen, Xiaoni Yang, Lianqiao Yang, Shiping Guo
Summary: The effect and mechanism of carrier gas velocity, V/III ratio, and carrier gas velocity match on the growth rate of AlN were investigated in this study. The results showed that the growth rate of AlN initially increased with hydrogen flow rate, reached saturation, and then decreased monotonically. The turning point value depended on the equipment and process. By increasing the MO VM, the growth rate of AlN could be improved, but the uniformity deteriorated due to turbulence and loss of uniform boundary layer. High quality AlN films were successfully grown on nano-patterned sapphire substrates with improved crystalline quality and atomic smooth surfaces.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Tingting Ma, Yang Li, Kangning Sun, Qinglin Cheng, Sen Li
Summary: This study investigates the melting process and nucleation behavior of sodium crystals using molecular dynamics simulation. The results show good agreement between simulated and experimental values for the melting temperature, density, and radial distribution function of sodium. The diffusion coefficient of liquid sodium increases linearly with temperature, and the homogeneous nucleation rate of melting in superheated sodium crystal exponentially increases with temperature. The findings provide theoretical support for applications involving heat and mass transfer in sodium-related systems.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Hisato Nishii, Shintarou Iida, Akira Yamasaki, Takumi Ikenoue, Masao Miyake, Toshiya Doi, Tetsuji Hirato
Summary: Epitaxial V2O3 films were fabricated on sapphire substrates using mist chemical vapor deposition (mist CVD) method, eliminating the need for high vacuum conditions. The films can be grown on sapphire substrates even under atmospheric pressure, with the optimal growth temperature at 823 K. The films grown at 823 K exhibit a metal-insulator transition at approximately 155 K. The film on C-plane sapphire exhibits a lower transition temperature compared to those on R- and A-plane sapphire substrates.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Jani Jesenovec, Kevin Zawilski, Peter Alison, Stephan J. Meschter, Sambit K. Saha, Andrew J. Sepelak, Peter G. Schunemann
Summary: In this study, NiSb needles were successfully formed in InSb by manipulating the growth rate and adding NiSb. These needle structures in InSb can be used to tune the magnetoresistance of devices. Additionally, undoped InSb crystals demonstrated good infrared transmission at low growth rates.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
D. Joseph Daniel, P. Karuppasamy, H. J. Kim
Summary: The 2-amino 4-methyl pyridinium oxalate (2A4MPO) compound was synthesized and its crystal structure, functional groups, thermal stability, electrical properties, and third-order nonlinear optical properties were studied. The results demonstrate that the synthesized crystal has good structural integrity, thermal stability, and potential for third-order nonlinear optical applications.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
C. W. Lan
Summary: The past two decades have witnessed a significant transformation in solar silicon crystal growth, especially in the competition between multi-crystalline silicon (Multi-Si) and mono-crystalline silicon (Mono-Si). The demand for this crucial material has exponentially surged, with silicon solar panels capturing over 95% of the global PV market share. The advancements in crystal growth technology during this period have set historical benchmarks, with the market share shifting from high-performance multi-crystalline silicon (HPM-Si) to CZ silicon.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Peiyao Hao, Lili Zheng, Hui Zhang
Summary: A novel design of argon gas tube for removing impurities during silicon ingot growth was developed, and numerical simulations showed that it can effectively extract SiO.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Geetika Sahu, Chanchal Chakraborty, Subhadeep Roy, Souri Banerjee
Summary: This article discusses the novel fractal nature of hydrothermally synthesized MoS2 QDs. By adjusting the reaction time, the study found that the average size of QDs increases and then decreases with longer reaction times. STEM images indicate that shorter reaction times lead to sheet formation, while extended reaction times cause sheets to fragment into QDs.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Pengjian Lu, Wei Huang, Junjun Wang, Haitao Yang, Shiyue Guo, Bin Li, Ting Wang, Chitengfei Zhang, Rong Tu, Song Zhang
Summary: A systematic study on the tetramethylsilane-hydorgen (TMS-H-2) system for the deposition of pure single-crystal SiC by high-temperature chemical vapor deposition (HTCVD) method is conducted. The study investigates the effect of temperature, pressure, and H-2:TMS ratio on the deposition conditions and provides a theoretical basis and guidance for improving the quality and cost of industrial production of single-crystal SiC.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Xinyu Jiang, Liangliang Liu, Yanqing Liu, Yan Wang, Zhaoping Hou
Summary: Investigation on the preparation of anisometric templated textured high entropy or multi-element doped ferroelectric ceramics was conducted using A-site disordered niobate microcrystals. The effects of process parameters on the morphology and chemical composition were studied, and the photocatalytic properties of the microcrystals were evaluated.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Mobashsara Tabassum, Md. Ashraful Alam, Sabrina Mostofa, Raton Kumar Bishwas, Debasish Sarkar, Shirin Akter Jahan
Summary: In this study, high crystallinity copper nanoparticles were synthesized by altering the reaction medium at low temperatures. The results show that changing the reaction medium can reduce the surface energy of precursors and promote the formation of highly crystalline copper nanoparticles.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Ivan Bodnar, Vitaly V. Khoroshko, Veronika A. Yashchuk, Valery F. Gremenok, Mohsin Kazi, Mayeen U. Khandaker, Tatiana I. Zubar, Daria I. Tishkevich, Alex Trukhanov, Sergei Trukhanov
Summary: This work presents the production of single crystals of Cu2ZnGeSe4, a semiconducting quaternary compound, using a gas chemical method with iodine as a transporter. The phase state, crystal structure, and lattice constants of the synthesized samples were refined and determined. The band gap of Cu2ZnGeSe4 was calculated using transmission spectrum and it was found that the band gap increases by 12% with decreasing temperature in the range of 20-300 K.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Timur Malin, Igor Osinnykh, Vladimir Mansurov, Dmitriy Protasov, Sergey Ponomarev, Denis Milakhin, Konstantin Zhuravlev
Summary: The effect of growth temperature on the buffer leakage currents of GaN-on-Si layers was investigated. It was found that higher growth temperature results in lower leakage currents. The defects in GaN layers grown at different temperatures were studied using photoluminescence technique, and a correlation between leakage currents, structural perfection, and donor concentration in GaN-on-Si layers was established. It was also observed that reduced growth temperature leads to the formation of inversion domains.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Thi-Hoai-Thu Nguyen, Jyh-Chen Chen
Summary: The effect of heater power control on heat, flow, and oxygen transport for CCz crystal growth was studied. Shorter upper side heater design could improve crystal quality and growth, but with higher power consumption.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Peter Rudolph
Summary: This article presents an overview of selected contributions to the development of crystal growth technology by the Laudise Prize awardee 2023. It discusses various aspects such as shaped crystal growth, the correlation between melt structure and crystal quality, control of intrinsic defects and inclusions, prevention of dislocation cell patterns, and melt growth experiments under a travelling magnetic field.
JOURNAL OF CRYSTAL GROWTH
(2024)