Article
Materials Science, Multidisciplinary
M. Isik, N. M. Gasanly
Summary: In this study, Al-doped ZnO nanostructured thin films were produced using AZO ink, and their structural characteristics were analyzed using XRD and SEM techniques. The results showed that the AZO thin films had a well-defined hexagonal crystal structure, and the size of the nanostructure particles varied between 20 and 30 nm. It was also found that the bandgap energy of the Al-doped ZnO nanostructured films changed with temperature, and this temperature-bandgap energy dependency was studied using transmission experiments and mathematical models.
Article
Engineering, Electrical & Electronic
A. Ayana, Neelamma B. Gummagol, Parutagouda Shankaragouda Patil, Pankaj Sharma, B. V. Rajendra
Summary: The Zn1-xLaxO nanofilms were prepared using chemical spray pyrolysis technique at 723K, with La3+ ion doping resulting in the smallest crystalline size and highest dislocation density. Changes in surface morphology were observed with increased dopant concentration. Different properties such as absorption edge shifts and optical coefficients were affected by the La3+ incorporation in the deposits.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Yan Xu, Yuting Xu, Jie Sun, Yunkai Mao, Zhen Chai, Jianli Li
Summary: A new spin-selective beam-splitting metasurface-based technique for atomic spin detection is proposed in this study. The experimental results show that the fabricated metasurface supports the beam splitting focusing of circular polarized light. Compared with the traditional beam splitter, this method can reduce the probe's optical path volume by at least 80% and enhance the integration of atomic sensors.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Engineering, Multidisciplinary
Maya Chauhan, Vinod Kumar Singh
Summary: This study reports an intensity-modulated and reflection-based salinity sensor using ZnO nanorods coating. The sensor shows good sensitivity, reproducibility, and durability, making it suitable for monitoring and controlling salt concentration in water resources.
Article
Engineering, Electrical & Electronic
Han Wu, Ying Wang, Lichao Zhang, Kuikui Guo, Yijian Huang, Changrui Liao, Yiping Wang
Summary: The proposed simple deep UV sensor consists of a conventional single-mode optical fiber and a ZnO microwire, with the microwire acting as a Fabry-Perot interferometer for UV light monitoring. The interference wavelengths of the device exhibit red-shift under 266-nm deep UV laser irradiation, with a sensitivity of 0.288 nm/(W center dot cm(-2)) and a fast response time of 0.56 ms, showing promise for highly spatial-resolved optical fiber UV sensors.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Mohamed Manoua, Nejma Fazouan, Abdelmajid Almaggoussi, Najoua Kamoun, Ahmed Liba
Summary: In this study, an n-ZnO/p-Si heterojunction was prepared using sol-gel spin-coating technique and analyzed by 2D numerical simulations. The material exhibited characteristics such as hexagonal wurtzite structure, high optical transmittance, and intrinsic defects. Various properties like charge carrier density, mobility, and resistivity were measured, along with photoelectric parameters under illumination. Simulation using Atlas Silvaco software revealed the presence of interface states density that impacts the photoelectric performance of the structure.
Article
Engineering, Electrical & Electronic
Guiying Zhang, Hongjian Zeng, Gaobo Tan, Qiang Lin
Summary: This paper proposes an integrated design approach for VCSEL-based SERF magnetometers. By using optical rotation detection instead of absorption detection, a high-sensitivity magnetometer can be implemented while effectively suppressing VCSEL noise.
IEEE SENSORS JOURNAL
(2022)
Article
Nanoscience & Nanotechnology
Mingang Zhang, Xiangdong Xu, Jinrong Liu, Yadong Jiang, Jun Wang, Ningning Dong, Chenduan Chen, Baohua Zhu, Yuning Liang, Ting Fan, Jimmy Xu
Summary: Given the substantial pi-electron delocalization observed in 4-N,N-dimethylamino-4'-N'-methyl-stilbazolium tosylate (DAST), a high third-order nonlinear optical response can be expected. In this study, all-organic DAST-polymethyl methacrylate (PMMA) composite films were prepared and their nonlinear absorption performances were measured. The results showed that the composite films exhibited giant optical limiting (OL) responses, high flexibility, and excellent environmental stability. This suggests that these all-organic composite films have great potential for applications in flexible OL devices.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Electrical & Electronic
Dong-Pyo Han, Gyeong Won Lee
Summary: This study aims to understand and elucidate the physical factors limiting the wall-plug efficiency (WPE) in modern light-emitting diodes (LEDs) by comparing two different LED material systems. Analysis showed that carrier dynamics depend on the material systems, with potential for improving WPE through strategies tailored to each material, such as improving light extraction in red samples and suppressing carrier accumulation in blue samples.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2021)
Article
Electrochemistry
Marya Khan, Vandana Nagal, Sakeena Masrat, Talia Tuba, Nirmalya Tripathy, Mohammad K. Parvez, Mohammed S. Al-Dosari, Ajit Khosla, Hidemitsu Furukawa, A. K. Hafiz, Rafiq Ahmad
Summary: An EGT-based biosensor utilizing Fe2O3 nanoparticles decorated ZnO nanorods was developed for cholesterol detection, showing high sensitivity and a wide linear range. This biosensor demonstrated excellent specificity, reproducibility, stability, and applicability in real serum samples, making it a promising platform for future analyte detection.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Engineering, Electrical & Electronic
Yue Feng, Han Liang, Tianyu Yang, Chi Liu, Aina Gong, Tao Shen
Summary: A novel UV sensor based on MFC-MZI structure coated with ZnO and ZnO composite graphene was proposed in this study. The experimental results demonstrated high sensitivity of the sensor for UV sensing, offering potential applications in various fields.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Harith Ahmad, Nima Naderi, Kavintheran Thambiratnam, Mohammad Faizal Ismail, Muhammad Zharif Samion
Summary: Zinc oxide microspheres were deposited on polycarbonate substrates using the electrochemical deposition technique with the help of glycerol. The microspheres were formed by the assembly of nanoplatelets, which were grown using a computer-controlled potentiostat. The ZnO nanostructures exhibited high sensitivity to incident photons and showed stable photoelectric behavior under various bending conditions, making them suitable for applications in flexible photodetectors.
SENSORS AND ACTUATORS A-PHYSICAL
(2023)
Article
Materials Science, Multidisciplinary
Yu-Cheng Chang, Shih-Yue Syu, Zi-Ying Wu
Summary: The zinc oxide-indium sulfide composite nanofiber is fabricated through electrospinning process, serving as a promising candidate for highly efficient hydrogen evolution photocatalyst by enhancing photocatalytic hydrogen production activity and increasing electron-hole pairs separation.
Article
Engineering, Electrical & Electronic
Tonglei Cheng, Fan Zhang, Bin Li, Wei Liu, Xiaoyu Chen, Yuanhongliu Gao, Xin Yan, Xuenan Zhang, Fang Wang, Takenobu Suzuki, Yasutake Ohishi
Summary: A Sagnac interferometer based optical fiber ultraviolet (UV) sensor utilizing ZnO film to convert UV irradiance changes to interference spectrum wavelength shifts has been proposed. The sensor showed competitive sensitivity, high linearity, satisfactory repeatability, and stability.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Optics
Ting Lei, Changyu Zhou, Dawei Wang, Zhenwei Xie, Boyuan Cai, Shecheng Gao, Youpeng Xie, Luping Du, Zhaohui Li, Anatoly Zayats, Xiaocong Yuan
Summary: A chip-integrated nanodisk device is demonstrated for high-speed coherent optical signal detection based on spin-orbit coupling in silicon photonics circuitry. The device can extract phase information through polarization measurements, enabling coherent signal recovery at multiple wavelengths. This technology offers low-cost and small footprint advantages in high-speed coherent optical communication applications.
LASER & PHOTONICS REVIEWS
(2022)
Article
Chemistry, Physical
Bin Zhang, Johan Klarbring, Fuxiang Ji, Sergei Simak, Igor A. Abrikosov, Feng Gao, Galyna Yu Rudko, Weimin M. Chen, Irina A. Buyanova
Summary: Phonon-phonon and electron/exciton-phonon coupling are found to play a vital role in the thermal, electronic, and optical properties of metal halide perovskites. Our study focuses on the evaluation of phonon anharmonicity and coupling between electronic and vibrational excitations in the novel material, Cs2NaFeCl6, through Raman measurements and theoretical calculations. The results highlight the significance of phonon-phonon and electron-phonon interactions in the electronic properties of Cs2NaFeCl6.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Materials Science, Coatings & Films
Jian-Sian Li, Xinyi Xia, Chao-Ching Chiang, David C. C. Hays, Brent P. P. Gila, Valentin Craciun, Fan Ren, S. J. Pearton
Summary: The characteristics of sputtered NiO for pn heterojunctions with Ga2O3 were investigated, and it was found that the oxygen/nickel and Ni2O3/NiO ratios, as well as the bandgap and resistivity, increased with the O-2/Ar gas flow ratio. However, the bandgap and Ni2O3/NiO ratio decreased with increasing annealing temperature, resulting in higher film density. The incorporation of hydrogen into NiO during plasma exposure was confirmed, and the band alignments of NiO films with both alpha- and beta-Ga2O3 were determined to have type II-staggered gaps. The breakdown voltage of NiO/beta-Ga2O3 heterojunction rectifiers also varied with the O-2/Ar flow ratio during deposition.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Materials Science, Coatings & Films
Benjamin C. Letson, Simon Barke, Peter Wass, Guido Mueller, Fan Ren, Stephen J. Pearton, John W. Conklin
Summary: The laser interferometer space antenna (LISA), a joint ESA and NASA project, will enable space-based gravitational wave detection. Three identical spacecraft will form a triangular configuration, flying in a drag-free formation around free-falling test masses. To compensate for test mass charging, UV photons with higher energy than gold's work function are needed. The performance of UV light emitting diodes (LEDs) for the LISA mission was characterized under various operating conditions, and degradation was found to be faster at elevated temperatures and in dc conditions. Preselection based on initial spectral ratio and ideality factor showed positive correlation with subsequent reliability. The UV LEDs for LISA are required to support a 2-year cruise and commissioning period, followed by a 4-year science mission.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Review
Materials Science, Multidisciplinary
Benjamin C. Letson, John W. Conklin, Peter Wass, Simon Barke, Guido Mueller, Md Abu Jafar Rasel, Aman Haque, Stephen J. Pearton, Fan Ren
Summary: There are various applications for deep UV AlGaN Light-Emitting Diodes (LEDs), including virus inactivation, air and water purification, sterilization, bioagent detection, and UV polymer curing. The long-term stability of these LEDs is important for space missions such as the Laser Interferometer Space Antenna (LISA). The literature review shows that the decline in output power of these LEDs over extended operating times is mainly driven by current and temperature, with the degradation rate dependent on the cube of drive current density and exponentially on temperature. The main mechanism for this decline is believed to be the creation/migration of point defects. Pre-screening based on the ratio of band edge-to-midgap emission and LED ideality factor can identify devices with long lifetimes (>10,000 h).
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2023)
Article
Physics, Applied
Y. Q. Huang, V Polojarvi, A. Aho, R. Isoaho, T. Hakkarainen, M. Guina, I. A. Buyanova, W. M. Chen
Summary: This study demonstrates the existence of nonlinear spin response in nonmagnetic materials and showcases it in a (Ga, N)As-InAs quantum dot coupled all-semiconductor nanostructure. The observed spin nonlinearity can be conveniently tuned with an external magnetic field and potentially operates at a speed exceeding 1 GHz.
PHYSICAL REVIEW APPLIED
(2023)
Article
Crystallography
Jian-Sian Li, Hsiao-Hsuan Wan, Chao-Ching Chiang, Xinyi Xia, Timothy Jinsoo Yoo, Honggyu Kim, Fan Ren, Stephen J. Pearton
Summary: Vertical heterojunction rectifiers with p-type NiO and thick Ga2O3 drift layers grown on Sn-doped β-Ga2O3 substrates exhibited breakdown voltages > 8 kV. Low drift doping concentration, low power during NiO deposition, and the formation of a guard ring were key factors for achieving excellent performance. These results demonstrate the potential of NiO/Ga2O3 rectifiers beyond SiC and GaN.
Article
Materials Science, Multidisciplinary
Fuxiang Ji, Johan Klarbring, Bin Zhang, Feng Wang, Linqin Wang, Xiaohe Miao, Weihua Ning, Muyi Zhang, Xinyi Cai, Babak Bakhit, Martin Magnuson, Xiaoming Ren, Licheng Sun, Mats Fahlman, Irina A. Buyanova, Weimin M. Chen, Sergei I. Simak, Igor A. Abrikosov, Feng Gao
Summary: Lead-free halide double perovskites (HDPs) have been synthesized with remarkable and fully reversible thermochromism. The thermochromism in Cs2NaFeCl6 is attributed to electron-phonon coupling, and it exhibits higher temperature sensitivity compared to lead halide perovskites and conventional semiconductors. The Cs2NaFeCl6 single crystal shows excellent environmental, thermal, and thermochromic cycle stability. This study provides valuable insights and new possibilities for developing efficient thermochromic materials.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Jian-Sian Li, Xinyi Xia, Chao-Ching Chiang, Hsiao-Hsuan Wan, Fan Ren, Jihyun Kim, S. J. Pearton
Summary: Neutrons generated by charge-exchange reactions were used to irradiate Schottky Ga2O3 rectifiers and NiO/Ga2O3 p-n heterojunction rectifiers. The breakdown voltage was improved for Schottky rectifiers but highly degraded for their NiO/Ga2O3 counterparts. The switching characteristics were degraded for both types of devices after irradiation.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Jian-Sian Li, Chao-Ching Chiang, Xinyi Xia, Hsiao-Hsuan Wan, Fan Ren, S. J. Pearton
Summary: Large area vertical NiO/β n-Ga2O/n(+) Ga2O3 heterojunction rectifiers with high breakdown voltage (3.6 kV) and large conducting currents (4.8 A) are demonstrated. The performance exceeds the unipolar 1D limit for GaN, indicating the potential of β-Ga2O3 for future high-power rectification devices. The breakdown voltage is strongly dependent on the carrier concentration in the drift region.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Bin Zhang, Yuqing Huang, Fuxiang Ji, Xiaohe Miao, Feng Gao, Weimin M. Chen, Irina A. Buyanova
Summary: We report the first observation of second harmonic generation (SHG) from halide double perovskite single crystals. The SHG efficiency of these materials with centrosymmetric crystalline structures is strongly dependent on the measurement temperature, increasing by up to 3 orders of magnitude at low temperatures under light illumination. The enhancement is attributed to the build-up of a light-induced electric field within the near-surface region.
Article
Crystallography
Jian-Sian Li, Hsiao-Hsuan Wan, Chao-Ching Chiang, Fan Ren, Stephen J. Pearton
Summary: The stability of vertical geometry NiO/Ga2O3 rectifiers was examined under two types of annealing. It was found that annealing at 300 degrees C resulted in the best performance, including maximizing breakdown voltage and on-off ratio, lowering forward turn-on voltage, reducing reverse leakage current, and maintaining on resistance. The surface morphology remained smooth and the NiO exhibited a bandgap of 3.84 eV with an almost unity Ni2O3/NiO composition.
Article
Materials Science, Multidisciplinary
Jian-Sian Li, Chao-Ching Chiang, Xinyi Xia, Hsiao-Hsuan Wan, Fan Ren, S. J. Pearton
Summary: NiO/β-Ga2O3 vertical rectifiers show near-temperature-independent breakdown voltages (V-B) of >8 kV at 600 K. The power figure of merit (V-B)²/R-ON for 100 μm diameter devices is 9.1 GW cm(-2) at 300 K and 3.9 GW cm(-2) at 600 K. In contrast, Schottky rectifiers on the same wafers have V-B of about 1100 V at 300 K with a negative temperature coefficient of breakdown. The power figure of merit for Schottky rectifiers is much lower compared to the heterojunction rectifiers. The results demonstrate the potential of using transparent oxide heterojunctions for high temperature, high voltage applications.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Review
Engineering, Electrical & Electronic
S. J. Pearton, Xinyi Xia, Fan Ren, Md Abu Jafar Rasel, Sergei Stepanoff, Nahid Al-Mamun, Aman Haque, Douglas E. Wolfe
Summary: Wide bandgap semiconductors SiC and GaN are used in power electronics and light-emitting diodes. They have higher radiation hardness compared to Si devices due to larger threshold energies for creating defects and high rates of defect recombination. However, heavy-ion-induced catastrophic burnout commonly occurs in SiC and GaN power devices. Light-emitting devices are not affected by this mechanism. Strain has also been identified as a parameter affecting radiation susceptibility of wide bandgap devices.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2023)
Article
Engineering, Electrical & Electronic
Chao-Ching Chiang, Hsiao-Hsuan Wan, Jian-Sian Li, Fan Ren, Timothy Jinsoo Yoo, Honggyu Kim, S. J. Pearton
Summary: Sputtered p-NiO films were used to suppress gate leakage and produce a positive shift in the gate voltage of AlGaN/GaN high-electron mobility transistors for e-mode operation. The utility of NiO gates in increasing the on-off ratio and shifting the threshold voltage in comparison to Schottky gates was demonstrated.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2023)
