Raman Spectroscopic Determination of Hole Concentration in p-Type GaSb
James E. Maslar, Wilbur S. Hurst, C Wang
Room temperature p-type GaSb bulk coupled mode spectra were measured as a function hole concentration. These spectra were obtained using an optical system based on 752.55 nm excitation in order to obtain more sensitivity to bulk GaSb coupled mode scattering than possible with visible wavelength excitation-based systems. A relatively simple spectral model for the electronic contribution to the dielectric function was evaluated for determination of hole concentration from the bulk coupled mode spectra. Optically-derived values for hole concentration were determined by minimizing the sum of the residuals squared between an experimental and simulated spectrum as a function of total hole concentration and a plasmon damping parameter. Hole concentrations obtained from the Raman spectroscopic measurements deviated from the values determined from single field Hall effect measurements that were corrected to account for two band conduction by ~20% to ~65%. These deviations were attributed to the limitations of the spectral model employed and uncertainties in GaSb materials properties.