Optical and electrical characterization of the InAlAs/InGaAs metamorphic high electron mobility transistor structures

• Main Authors: Chia-Cheng Hung, 洪嘉政
• Other Authors: Der-Yuh Lin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/92713536478136698556

碩士 === 國立彰化師範大學 === 電子工程學系 === 97 === We present the studies of two-dimensional electron gas (2DEG) in two (etched and nonetched) InGaAs/InAlAs/InGaAs metamorphic high electron mobility transistor (mHEMT) structures using photoluminescence (PL), photoconductivity (PC), Hall and photo-Hall measurements. These two samples were grown by metal-organic chemical vapor deposition (MOCVD) on semi-insulating GaAs substrate and were designated as A (etched) and B (nonetched). Sample A has the same layer with sample B but its Si doped cap layer has been etched. In the PL spectra, two optical features are observed, and they are identified to be the 11H and 21H transitions localized in the channel layer. It can be used to estimate related information about the energy positions of electron quantization levels, and Fermi level by fitting the PL spectra, and then the carrier concentration can be estimated at various temperatures. We also performed the Hall measurements at different temperatures. Compare the Hall data (including carrier concentration and mobility) of samples A and B, two conduction channels, the high mobility 2DEG in channel layer and the low mobility electrons in cap layer are observed. We also presented the PC and photo-Hall spectra, the intersubband transitions and the carrier concentration induced by photo illumination were observed. Absorption coefficient of the channel layer can be estimated from the photo-Hall spectra.