RECENT ADVANCES AND NOVEL APPROACHES OF P-TYPE DOPING OF ZINC OXIDE

Due to its high radiative stability and superior optoelectronic properties, such as wide direct band gap of similar to 3.4 eV and high exciton binding energy of similar to 60 meV, ZnO is considered for the fabrication of ultraviolet and visible light emitting and laser diodes, solar-blind photodetectors. Although proof-of-concept devices were already demonstrated, further progress in this area is slowed down by the difficulties of doping ZnO p-type. Here, we discuss problems associated with doping of ZnO, cover recent progress in this area, and discuss an alternative approach to increase p-type dopability via anion substitution, replacing oxygen with other group VI elements (S, Se, Te). We also propose that these anion-substituted alloys will be extremely promising for fabrication of photovoltaic devices, such as highly efficient thin film solar cells.