Photoluminescence characteristics of Cd and Zn diffused layers in InP

Cd and Zn diffused InP have been characterized using low temperature PL (photoluminescence). The diffusion was done at three temperatures using evaporated diffusion source in a rapid thermal annealer (RTA). Band to acceptor (B-A) transition dominates in the PL spectra of InP:Cd, whereas InP:Zn shows donor to acceptor (D-A) transitions with blue-shift tendency for higher excitation power. This indicates the presence of much higher concentration of interstitials acting as donors in InP:Zn than in InP:Cd. Furthermore the D-A peak in InP:Zn moves to lower energy (red-shift) for higher diffusion temperature, which is attributed to the increase in number of nonradiative recombination centers.