We report on the low-frequency electronic noise in (Al$_x$Ga$_{1-x}$)$_2$O$_3$ Schottky barrier diodes. The noise spectral density reveals 1/f dependence, characteristic of the flicker noise, with superimposed Lorentzian bulges at the intermediate current levels (f is the frequency). The normalized noise spectral density in such diodes was determined to be on the order of 10$^{-12}$ cm$^2$/Hz (f=10 Hz) at 1 A/cm$^2$ current density. At the intermediate current regime, we observed the random telegraph signal noise, correlated with the appearance of Lorentzian bulges in the noise spectrum. The random telegraph signal noise was attributed to the defects near the Schottky barrier. The defects can affect the local electric field and the potential barrier, and correspondingly, impact the electric current. The obtained results help to understand noise in Schottky barrier diodes made of ultra-wide-band-gap semiconductors and can be used for the material and device quality assessment.
Monitoring Gallium-Induced Damage in Aluminum Alloys Using Nonlinear Resonant Ultrasound Spectroscopy
Institute of Thermomechanics, Czech Academy of Sciences（捷克科学院热力学研究所）；Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague（布拉格捷克理工大学核科学与物理工程学院）；DISAT, Condensed Matter Physics and Complex Systems Institute, Politecnico di Torino（都灵理工大学生化与物理技术系凝聚态物理与复杂系统研究所）
Aluminum and Gallium Distribution in the Lu3(Al5-xGax)O12:Ce Multicomponent Garnet Scintillators Investigated by the Solid-State NMR and DFT calculations
用~（27）Al和~（71）Ga MAS NMR结合单晶~（71）Ga NMR研究了混合晶体Lu_3Al_（5-x）Ga_xO_（12）中Al和Ga原子在石榴石结构中四面体和八面体位置上的分布。在实验研究的基础上，采用密度泛函理论进行了理论计算，预测了混合石榴石中Ga取代Al的趋势。实验和理论结果表明，在石榴石结构中的四面体和八面体位置上的Al和Ga的不均匀分布，具有比Al更大的离子半径的Ga强烈偏好占据石榴石结构中具有较小体积的四面体位置。在密度泛函理论的框架下，计算了所有化合物的Al和Ga核的四极耦合常数和化学位移参数，并计算了Al和Ga核的电场梯度.
The Schottky diode, BN/GaN layered composite contacting to bulk aluminum, is theoretically plausible to harvest wireless energy above X-band. According to our first principle calculation, the insertion of GaN layers dramatically influences the optical properties of the layered composite. The relative dielectric constant of BN/GaN layered composite as a function of layer-to-layer separation is investigated where the optimized dielectric constant is 3.1. Furthermore, we design another Schottky diode via nanostructuring. Our first principle calculation suggests that the relative dielectric consta…
Electronic devices are extremely sensitive to defects in their constituent semiconductors, but locating electronic point defects in bulk semiconductors has previously been impossible. Here we apply scanning transmission electron microscopy (STEM) electron beam-induced current (EBIC) imaging to map electronic defects in a GaAs nanowire Schottky diode. Imaging with a non-damaging 80 or 200 kV STEM acceleration potential reveals a minority-carrier diffusion length that decreases near the surface of the hexagonal nanowire, thereby demonstrating that the device's charge collection efficiency (CCE) …
$β$-Ga${_2}$O${_3}$ based semiconductor devices are expected to have significantly improved high-power and high-temperature performance due to its ultra-wide bandgap of close to 5 eV. However, the high-temperature operation of these ultra-wide-bandgap devices is usually limited by the relatively low 1-2 eV built-in potential at the Schottky barrier with most high-work-function metals. Here, we report heterojunction p-NiO/n-$β$-Ga${_2}$O${_3}$ diodes fabrication and optimization for high-temperature device applications, demonstrating a current rectification ratio of more than 10${^6}$ at 410°C.…
High-Temperature Hydrogen Sensors Based on Gallium Oxide Heterojunction Diodes
Materials Science Center, National Laboratory of the Rockies（国家落基山实验室材料科学中心）；Department of Metallurgical and Materials Engineering, Colorado School of Mines（科罗拉多矿业学院冶金与材料工程系）
Atomic layer deposition (ALD) is an essential tool in semiconductor device fabrication that allows the growth of ultrathin and conformal films to precisely form heterostructures and tune interface properties. The self-limiting nature of the chemical reactions during ALD provides excellent control over the layer thickness. However, in contrast to idealized growth models, it is experimentally challenging to create continuous monolayers by ALD because surface inhomogeneities and precursor steric interactions result in island growth during film nucleation. Thus, the ability to create pin-hole free…
Utilizing (Al, Ga)2O3/Ga2O3 superlattices to measure cation vacancy diffusion and vacancy-concentration-dependent diffusion of Al, Sn, and Fe in \b{eta} -Ga2O3
本研究利用铝镓氧化物/氧化镓超晶格，通过新型有限差分方案提取了退火过程中阳离子空位及 Al、Sn、Fe 的扩散常数，发现衬底空位会扩散并与杂质相互作用，且未发现表面镓空位引入影响 Al 扩散，强调了控制非故意杂质的重要性。
