Homoepitaxial growth of ZnSe on dry-etched substrates

High quality ZnSe layers have been grown by molecular beam epitaxy on dry-etched ZnSe substrates. Surface damage caused by cutting and polishing of the ZnSe substrate was removed by dry etching using BCl3 gas to 10 μm depth. The dry-etched ZnSe substrates exhibited smooth surface morphology and showed excitonic emissions stronger than that from as-polished substrates in photoluminescence (PL) measurements at 11 K. The low-temperature PL spectra obtained from homoepitaxial ZnSe layers grown on the substrates dry etched at the optimum condition showed a strong free-exciton emission at 2.804 eV and a dominant donor-bound exciton emission at 2.798 eV. Since each excitonic emission shows a single peak, the homoepitaxial layers appear to be free from strain.