Infrared study and characterization of Zn diffused InP

Reflectance and transmittance spectra of p-type InP:Zn samples were measured by Fourier transform infrared spectroscopy (PTIR) in the spectral range from 40 to 700 cm-‘. Zn was diffused into InP by an open-tube method, and a subsequent short annealing at different temperatures for the electrical activation of Zn diffused layers was performed. Free-carrier effects on vibrational structures around the restrahlen peak were evidenced. Concentration of electrically active Zn and free-hole damping constant were obtained by fitting reflectance spectra
with a classical Drude-Lorentz dielectric function. The results confirmed the model for the electrical activation of the samples, based on outdiffusion of interstitial Zn by thermal annealing.