Engineering Commons^™

Carrier Transport In Ge Nanowires And One Dimensional Si/Ge Heterojunctions, Eun Kyu Lee

Theses

Ge Nanowires (Ge NWs) on single crystal, (100) and (111) oriented n-type Si substrates were grown via the vapor-liquid-solid (VLS) mechanism and studied with respect to their electrical properties.

Using different contact geometries, direct current (DC) and alternating current (AC) electrical and photoelectrical measurements were carried out at room temperature to investigate electrical properties of Ge NWs and Ge NWs/Si substrate one-dimensional (1 D) heterojunctions (HJs). A rectifying junction behavior is observed at NWs/substrate interface, but many orders of magnitude greater AC conductance than DC in Ge NW volume is measured at high frequencies. The obtained experimental data are consistent …

Simulation Of Hot Electron And Quantum Effects In Algan/Gan Heterostructure Field Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, H. Xu, M. S. Shur, M. Asif Khan, Grigory Simin, J. Yang

Faculty Publications

We report on simulations of electrical characteristics of AlGaN/(InGaN)/GaN heterostructurefield effect transistors with quantum and hot electroneffects taken into account. Polarization charges lead to quantum confinement of electrons in the channel and to the formation of two-dimensional electron gas. The electron quantization leads to the spread of the electronwave function into the barrier and bulk but does not have significant impact on dc electrical characteristics.Hot electrons play an important part in the charge transport by spilling over into the bulk GaN where they are captured by traps. This leads to negative differential conductivity, which is also observed experimentally. The simulation …