P-type conductivity control of ZnSe with insertion of ZnTe:Li submonolayers in metalorganic molecular-beam epitaxy

Abstract

p-type ZnSe with periodic insertion of ZnTe:Li submonolayers was grown by metalorganic molecular-beam epitaxy. The net acceptor concentration, NA–ND, up to 2×1017–5×1018 cm−3 was observed. However, under higher Li doping, reduction of the growth rate was observed and the growth direction of the islands on the surface changed from the [01̄1] to [011] direction. This resulted in samples not uniformly doped along the growth direction especially for higher Li doping. This reduction of the growth rate was attributed to the adsorption of Li to the B steps, and this phenomenon was suppressed by a periodic Zn purge to the growing surface. By this method, we could keep the growth rate constant and succeeded in obtaining samples which are doped uniformly along the growth direction for higher Li doping. NA–ND up to 4.5×1017 cm−3 was measured in this way. The photoluminescence peaks were blueshifted and discrete peaks were observed with increasing Li doping. This interesting behavior was explained with a ZnTe quantum box model.