Raman Spectroscopy of n-Type and p-Type GaSb with Multiple Excitation Wavelengths

Maslar JE, Hurst WS, Wang CA

关键词: EXCITATION;    OPTICAL SYSTEMS;    PERFORMANCE;    PROBES;    RAMAN SPECTRA;    RAMAN SPECTROSCOPY;    SCATTERING;    SPACE CHARGE;    SPECTRA;    WAVELENGTHS;   

DOI  :  10.2172/903186
RP-ID  :  LM-07K002
PID  :  OSTI ID: 903186
Others  :  TRN: US200720%%201

学科分类：工程和技术（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

The interpretation of Raman spectra of GaSb can be complicated by the presence of a so-called surface space charge region (SSCR), resulting in an inhomogeneous near-surface Raman scattering environment. To fully interpret Raman spectra, it is important to have an understanding of the SSCR profile relative to the Raman probe depth. However, a priori determination of even the actual SSCR width is not always possible for GaSb under a wide range of doping levels. The primary objective of this report is to provide a convenient reference to aid in the determination of relative contributions to an observed GaSb Raman spectrum of SSCR scattering and bulk scattering for a range of excitation wavelengths, doping levels, and SSCR widths and types. Hence, Raman spectra of both n-type and p-type doped GaSb epilayers were obtained using 488 nm, 514.5 nm, 647.1 nm, and 752.55 nm excitation radiation. Both n-type and p-type doped GaSb epilayers were selected for investigation because these layers exhibit the two different SSCR types that are typically encountered with as-grown GaSb and related materials. A range of doping levels were examined for each doping type so as to examine the effects of a varying SSCR width on the observed spectra. A secondary objective of this report is to demonstrate the performance of a spectroscopic system based on 752.55 nm excitation that is sensitive to bulk carrier properties in n-type and p-type doped GaSb epilayers over a wide doping range, unlike visible wavelength-based optical systems.