Article
Chemistry, Multidisciplinary
Waseem A. Hussain, Kyle N. Plunkett
Summary: New conjugated polymers containing dihexylanthradithiophene (DHADT) in the main chain were successfully synthesized by Stille, Sonogashira, and Yamamoto cross-coupling polymerization reactions. These polymers exhibit notable optical features and are suitable for use in organic field effect transistors.
Article
Engineering, Electrical & Electronic
Daniel M. Dryden, Kyle J. Liddy, Ahmad E. Islam, Jeremiah C. Williams, Dennis E. Walker, Nolan S. Hendricks, Neil A. Moser, Andrea Arias-Purdue, Nicholas P. Sepelak, Kursti DeLello, Kelson D. Chabak, Andrew J. Green
Summary: We demonstrate a passivated MESFET fabricated on (010) Si-doped beta-Ga2O3 with breakdown over 2.4 kV without field plates, high Power Figure of Merit (PFOM), and high estimated Huang's Material Figure of Merit (HMFOM), owing to low gate charge and high breakdown. MESFETs with 13 μm source-drain spacing and 75 nm channel exhibited a current density of 61 mA/mm, peak transconductance of 27 mS/mm, and on-resistance of 133 Ω•mm. The device showed a PFOM competitive with state-of-the-art beta-Ga2O3 devices and a record high estimated HMFOM for a beta-Ga2O3 device, competitive with commercial wide-band gap devices. This demonstrates high-performance beta-Ga2O3 devices as viable multi-kV high-voltage power switches.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Chemistry, Physical
Shamshad A. Khan, R. M. Sahani, Ravi P. Tripathi, M. Shaheer Akhtar, Archana Srivastava
Summary: Bulk Se85Te15-xBix chalcogenide glasses were synthesized using melt quenching technique, and nanothin chalcogenide films of Se85Te15-xBix alloys were deposited on glass/Si wafer by PVCT. The optical and structural properties were analyzed by exposing the films to different doses of gamma irradiation, which led to variations in optical parameters and an increase in indirect band gap with higher irradiation doses. These changes were attributed to increased disorder and lattice strain caused by gamma irradiation.
RADIATION PHYSICS AND CHEMISTRY
(2021)
Article
Nuclear Science & Technology
Jonathan Lee, Andrew C. Silverman, Elena Flitsiyan, Minghan Xian, Fan Ren, S. J. Pearton
Summary: The effects of neutron radiation on silicon-doped ss-Ga2O3 were investigated using rectifiers or transistors as the measurement platform. The results showed an increase in reverse bias leakage current in rectifiers but little effect on reverse recovery switching time. Differences in CL spectra were observed between vertical and lateral device structures, highlighting the importance of impurities and defects. Furthermore, ss-Ga2O3 was found to be more resistant to radiation damage compared to other wide bandgap semiconductors.
RADIATION EFFECTS AND DEFECTS IN SOLIDS
(2023)
Article
Engineering, Electrical & Electronic
Yuji Ando, Hidemasa Takahashi, Ryutaro Makisako, Akio Wakejima, Jun Suda
Summary: This article reports the radio frequency characteristics of 150-nm gate aluminum gallium nitride (AlGaN)/gallium nitride (GaN) high electron mobility transistors (HEMTs) fabricated using i-line stepper lithography and a thermal reflow technique. The authors have developed two different gate structures, a field-plated gate using the lift-off process and a Y-shaped gate using the ion-milling process. The HEMTs fabricated with these gate structures exhibited similar DC characteristics, but the Y-shaped gate device showed slightly better high-frequency performance.
ELECTRONICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Samreen Khan, Frank Angeles, John Wright, Saurabh Vishwakarma, Victor H. Ortiz, Erick Guzman, Fariborz Kargar, Alexander A. Balandin, David J. Smith, Debdeep Jena, H. Grace Xing, Richard Wilson
Summary: The study aims to investigate the impact of bulk vibrational properties and interfacial structure on thermal transport at interfaces in wide band gap semiconductor systems. The results suggest that thermal conductance depends on the bulk phonon properties of the softer material and the interfacial structure, rather than just the vibrational similarity between the two materials.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Jun-Jie Wang, Can Fu, Hai-Yang Cheng, Xiao-Wei Tong, Zhi-Xiang Zhang, Di Wu, Li-Miao Chen, Feng-Xia Liang, Lin-Bao Luo
Summary: The study introduces a non-wide band gap semiconductor ultraviolet photodetector utilizing silicon nanowire arrays, which exhibit sensitivity to UV light but insensitivity to visible and infrared light. This novel device shows promise for sensitive UV photodetectors, with characteristics comparable to or even better than traditional wide band gap semiconductor devices.
Article
Materials Science, Multidisciplinary
Fuming Wu, Yixuan Liu, Jun Zhang, Xiangxiang Li, Hui Yang, Wenping Hu
Summary: In this study, high-mobility stretchable semiconducting blend films were prepared by blending a polymer semiconductor with an elastomer. The resulting blend films have low crystallinity and high aggregation degree, resulting in high stretchability and high mobility. The fully stretchable organic transistors exhibit high hole maximum mobilities at various strains and show high mechanical robustness during repeated stretching-releasing cycles.
SCIENCE CHINA-MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
[Anonymous]
Summary: Authors are requested to submit unpublished manuscripts for inclusion in an upcoming event.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Materials Science, Multidisciplinary
Shalima Shawuti
Summary: The research aimed to compare oxide semiconductors as electrolyte materials for intermediate temperature solid oxide fuel cells. Among them, CoGa2O4 exhibited the highest ionic conductivity values in a specific grain size range.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Marina S. S. Polinskaya, Askold A. A. Trul, Oleg V. V. Borshchev, Maxim S. S. Skorotetcky, Victoria P. P. Gaidarzhi, Siyovush K. K. Toirov, Daniil S. S. Anisimov, Artem V. V. Bakirov, Sergey N. N. Chvalun, Elena V. V. Agina, Sergey A. A. Ponomarenko
Summary: This study investigates the synthesis and behavior of organosilicon derivatives of benzothieno[3,2-b][1]benzothiophene (BTBT) at the water-air interface. The compounds with different lengths of terminal alkyl groups or without them were obtained with high yields and purity. The investigation showed that the compounds form crystalline phases at room temperature, but exhibit different mesophases at elevated temperatures depending on the presence and length of the terminal alkyl groups. The electrical properties of monolayer OFETs based on these compounds and their sensing responses to NO2 were also studied, revealing the dependence of charge carrier mobility and sensitivity parameters on the surface morphology of organic semiconductors.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Physical
Maciej J. Winiarski
Summary: This study investigated the electronic structures of ternary alloys of group III and rare earth nitrides, revealing that the introduction of rare earth ions can affect the band gap width. The findings suggest potential applications of these materials, encouraging further experimental investigations.
Article
Materials Science, Multidisciplinary
Jinseok Kim, Junyoung Choi, Youngho Kang
Summary: Using first-principles calculations, alkaline earth tellurides MTe (M = Sr or Ba) are shown to be promising wide-band-gap semiconductors that can be ambipolarly doped and transparent to visible light. With large direct band gaps (3.74 eV for SrTe and 3.09 eV for BaTe), 100 nm thick MTe films exhibit significant transmittance (over 80%) for visible light. The effective mass of electrons and holes in MTe is predicted to be small (<1 m0), enabling high carrier mobilities.
CURRENT APPLIED PHYSICS
(2023)
Article
Materials Science, Ceramics
Zhongqing Xiang, Huijuan Guan, Bing Zhang, Yafei Zhao
Summary: This study successfully prepared a unique photocatalyst composed of CoP and ZnIn2S4 (ZIS) through electrostatic self-assembly method, exhibiting significantly enhanced photocatalytic performance and excellent stability. These results are attributed to the large/intimate contact interface and the photo/electro-chemical properties of ZIS and CoP, improving light absorption, facilitating photoelectron transport and suppressing charge recombination.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2021)
Review
Chemistry, Multidisciplinary
Yuqiu Lei, Peiyun Li, Yuting Zheng, Ting Lei
Summary: Organic electrochemical transistors (OECTs) have shown great potential in various applications due to their high transconductance, low operating voltages, and good biocompatibility. However, the development of n-type and ambipolar OECT materials has lagged behind, which has limited the advancement of OECT-based logic circuits.
MATERIALS CHEMISTRY FRONTIERS
(2023)
Article
Physics, Applied
Jian-Sian Li, Chao-Ching Chiang, Xinyi Xia, Sergei Stepanoff, Aman Haque, Douglas E. Wolfe, Fan Ren, S. J. Pearton
Summary: NiO/Ga2O3 heterojunction rectifiers were irradiated with 1 Mrad of Co-60 gamma-rays, resulting in a 1000x reduction in forward current, a 100x increase in reverse current, and a significant decrease in the on-off ratio. The carrier concentration in the Ga2O3 drift region slightly decreased, indicating a reversible effect. The rectifiers showed no permanent ionizing dose effects and resistance to displacement damage, suggesting potential applications in harsh radiation environments with appropriate bias sequences.
JOURNAL OF APPLIED PHYSICS
(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)
Article
Physics, Applied
Md Abu Jafar Rasel, Ryan Schoell, Nahid Sultan Al-Mamun, Khalid Hattar, C. Thomas Harris, Aman Haque, Douglas E. Wolfe, Fan Ren, Stephen J. Pearton
Summary: This study investigated the effects and mechanism of IL-37 on pyroptosis in RA-FLSs induced by TNF-a. It was found that IL-37 inhibited inflammation and reduced pyroptosis-related protein expression in RA-FLSs. The study also revealed that IL-37 alleviates TNF-a-induced pyroptosis in RA-FLSs by inhibiting NF-?B/GSDMD signaling.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Materials Science, Coatings & Films
A. Y. Polyakov, A. I. Kochkova, Amanda Langorgen, Lasse Vines, A. Vasilev, I. V. Shchemerov, A. A. Romanov, S. J. Pearton
Summary: The study investigates the relationship between the emission rate of deep traps called E1 traps and the electric field dependence. The results demonstrate that the activation energy of the centers and the ratio of high-field to low-field electron emission rates follow a linear relationship with the square root of electric field at a fixed temperature, indicating the deep donor behavior of these traps. The possible microscopic nature of these centers is discussed based on recent theoretical calculations, and the most likely candidates are proposed to be Si-Ga1-H or Sn-Ga2-H complexes.
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
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
Engineering, Electrical & Electronic
Sergei P. Stepanoff, Aman Haque, Fan Ren, Stephen Pearton, Douglas E. Wolfe
Summary: The susceptibility of electronics to radiation increases as the size and complexity of electronic chips or systems increase. This study develops an indirect technique to identify radiation-susceptible regions and demonstrates its effectiveness in rapid detection.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(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
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
Crystallography
Chao-Ching Chiang, Jian-Sian Li, Hsiao-Hsuan Wan, Fan Ren, Stephen J. Pearton
Summary: Ga2O3 heterojunction rectifiers with NiO as the solution on the p-type side have become a novel candidate for power conversion applications. In this study, the optimized design of high-breakdown NiO/Ga2O3 rectifiers was examined using the Silvaco TCAD simulator to determine the electric field distribution. The doping concentration, guard ring thickness, and extension beyond the anode were all important factors in determining the breakdown location. The transition phenomenon from the edge of the NiO extension to the top contact periphery was found to be correlated with the depletion effect.
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)
