Using High-Frequency Surface-Acoustic-Wave to Probe Magnetotransport property of Semiconductor Two-Dimensional Electron System

碩士 === 國立中興大學 === 物理學系 === 90 === We report the conductivity variations of two-dimensional electron systems (2DESs) confined in semiconductor heterostructures in low-temperature (~0.4K) and high-magnetic-field environments by using high-frequency surface acoustic waves (SAWs) generated by an inter d...

Full description

Bibliographic Details
Main Author: 鄭憲明
Other Authors: 孫允武
Format: Others
Language:zh-TW
Published: 2002
Online Access:http://ndltd.ncl.edu.tw/handle/13045184024452405297
Description
Summary:碩士 === 國立中興大學 === 物理學系 === 90 === We report the conductivity variations of two-dimensional electron systems (2DESs) confined in semiconductor heterostructures in low-temperature (~0.4K) and high-magnetic-field environments by using high-frequency surface acoustic waves (SAWs) generated by an inter digital transducer (IDT) on a piezoelectric substrate (GaAs or LiNO3). The variations of SAW velocity and attenuation due to the conductivity change near the surface are detected by a phase-lock loop and a power detector respectively. We use pulse-modulated microwave signal and gated-averaging technique to reduce the heating and noise.