Common origin of doping-limiting mechanisms in IIB-VI compounds and alloys

Abstract Wide-band-gap II–VI semiconductors have a potential for a variety of applications, which are presently hindered by the difficulties in achieving efficient doping at both n - and p-side (above 10 18  cm −3 ). The origin and even more the microscopic nature of doping problems, remain controversial. In this paper, we have shown that for IIB–VI compounds or alloys the common origin of very different doping-limiting mechanisms can be traced down to the ratio of covalent radii of the constituent atoms (and respective vacancies). This ratio then determines the ratio of vacancy formation energies, and finally the ratio of their relative concentrations. The practical consequence is that the n - and p-type dopability of IIB–VI compounds as well as their ternary alloys can be predicted in a simple way. Limits of the approach are discussed.