OPTICAL-PROPERTIES OF CD-DIFFUSED AND ZN-DIFFUSED LAYERS IN INP

Cd- and Zn-diffused InP was characterized using low-temperature photol uminescence. The diffusion was done at three temperatures by evaporati ng a diffusion source in a rapid thermal annealer (RTA). Identical pro cess conditions were used for both dopants to compare the behavior of the two. The band-to-acceptor (B-A) transition dominate the InP:Cd PL spectra in which the donor-to-acceptor (D-A) peaks were not present. T he InP:Zn spectra showed both B-A and D-A transitions even though the D-A peak, which had a blue-shift tendency for higher excitation powers , was much stronger. This indicates the presence of a much higher conc entration of interstitials acting as donors in InP:Zn than in InP:Cd. Furthermore, the D-B peak in InP:Zn moved to lower energy (red-shift) for higher diffusion temperature, which is attributed to an increase i n the number of non-radiative recombination centers.