DOPING IN A SUPERLATTICE STRUCTURE - IMPROVED HOLE ACTIVATION IN WIDE-GAP II-VI MATERIALS

The activation energy of acceptors in ZnSe is about 110 meV and the ratio of the activated free holes to the doped acceptors is reduced for high doping. This paper proposes doping of acceptors in a superlattice structure to improve the activation ratio. The doping characteristics were analyzed considering self-consistent potential change due to the carrier distributions. The activation ratio is shown to be improved for the shorter period of the superlattice and free-hole concentrations of nearly 1×1019 cm-3 are expected in a ZnSe/ZnS0.18Se0.82 superlattice with a 60 Å period, which is about a 4-5 times improvement compared with the doping in ZnSe films.