MBE growth of a semiconductin gmaterial for blue light lasers

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We present the optimum growth conditions of lattice-matched ZnSxSel-x by MBE on (100)GaAs substrates. Surface morphology, X-ray diffraction and photoluminescence were investgated, and the optimum growth conditions were revealed as follows: The molecular beam intensity ratio of the group VI to II element is around 2.0 and the substrate temperature is 340゜C. The molecular beam retio means that the surface coverage fraction of the group VI and group II atoms are the same during growth. It is shown by comparing the photoluminescence spectra that the quality of the ZnS_xSe_<l-x> epilayers was higher than that of ZnSe.Nitrogen doped ZnS_xSe_<l-x> epilayers were grown on GaAs substrates using NH_3 as a doping gas. These layers were characterized mainly by photoluminescence. Exciton emissions bound to a neutral acceptor(^1_) were strongly observed in N-doped ZnSe. The acceptor level was determined to be 110meV by using Haynes' rule. The same value was obtained from the FA emission energy. We also observed the I^S_ emissions in lattice-matched ZnS_xSe_<l-x> epilayers, slthough these emissions were not the main emissions in the exciton emission region. The acceptor level was determined to be about 117 meV from the FA emission energy of ZnS_xSe_<l-x>:N. The FA emission intensities at 60K were proportionaly increased with increasing the NH_3 source supply. We attempted to increase the doping efficiency by cracking the NH_3.gas. The efficiencies slightly increased at around the cracking temperature of 300゜C, but the drastic improvement was not achieved. Morphologies and crystallinities of both N-doped ZnSe and ZnS_xSe_<l-x> were excellent and no deterioration due to N-doping was found.