Soohwan Jang

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A threshold reverse bias of ϳ21 V was observed leading to a sharp increase in the gate current of AlGaN/GaN high electron mobility transistors biased at low source-drain voltage ͑5 V͒. The gate current increases by one to two orders of magnitude at this bias, corresponding to an electric field strength around 1.8 MV cm −1. The gate current increased by(More)
Bartonella species were isolated from 49% of 128 cattle from California and Oklahoma, 90% of 42 mule deer from California, and 15% of 100 elk from California and Oregon. Isolates from all 63 cattle, 14 deer, and 1 elk had the same polymerase chain reaction/restriction fragment length polymorphism profiles. Our findings indicate potential for inter- and(More)
The characteristics of an acceptor level in Sb-doped, p-type ZnO were studied using cathodoluminescence ͑CL͒ spectroscopy as a function of hole concentration. Variable-temperature CL measurements allowed us to estimate the activation energy of an Sb-related acceptor from temperature-induced decay of CL intensity. The values of activation energy of about(More)
Minority electron diffusion length was measured in p-type, Sb-doped ZnO as a function of temperature using the electron beam induced current technique. A thermally induced increase of electron diffusion length was determined to have an activation energy of 184± 10 meV. Irradiation with a low energy ͑5 kV͒ electron beam also resulted in an increase of(More)
AlGaN/GaN High Electron Mobility Transistors were found to exhibit a negative temperature dependence of the critical voltage (V CRI) for irreversible device degradation to occur during bias-stressing. At elevated temperatures, devices exhibited similar gate leakage currents before and after biasing to V CRI , independent of both stress temperature and(More)
AlGaN/GaN High Electron Mobility Transistors (HEMTs) with various gate lengths have been step-stressed under both on-and off-state conditions. On-state, high power stress tests were performed on 0.17 lm gate length HEMTs and a single 5 lm spaced TLM pattern. Significant degradation of the submi-cron HEMTs as compared to the excellent stability of the TLM(More)
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