NIST logo

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

NIST Authors in Bold

Author(s): James E. Maslar; Wilbur S. Hurst; C Wang;
Title: Raman Spectroscopy of n-Type and p-Type GaSb with Multiple Excitation Wavelengths
Published: October 01, 2007
Abstract: 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. 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.
Citation: Applied Spectroscopy
Volume: 61
Issue: 10
Pages: pp. 1093 - 1102
Keywords: Raman Spectroscopy; GaSb; Surface space charge region; SSCR; Depletion layer; Accummulation layer.
Research Areas: Semiconductor Materials, Raman, Materials Science, Chemistry, Spectroscopy