Electrolyte electroreflectance study of laser annealing effects on the CdTe/Hg0.8Cd0.2Te (111) system

We have investigated the effects of laser annealing on the CdTe/Hg0.8Cd0.2Te (111) system by measuring the electrolyte electroreflectance (EER) spectra from both the CdTe layer as well as the interface region. The sample was a Hg0.8Cd0.2Te (111) single crystal with a 500-Å-thick polycrystalline CdTe film deposited on it; a section of the interface was annealed using the neodymium: yttrium aluminum garnet (Nd:YAG) laser 1.06-μm line. Our observations indicate the presence of strain due to lattice mismatch at the interface; laser annealing relieves this strain. In addition, the annealing also causes the diffusion of Hg ions from the interfacial region into the passivant layer. The changes in the line shapes of the EER spectra also show an improvement in the crystalline quality of the passivant layer.