Identification of the Native Vacancy Defects in Both Sublattices ofZnSxSe1−xby Positron Annihilation

We show how positron annihilation can distinguish vacancies in the different sublattices of a binary compound by performing experiments in ${\mathrm{ZnS}}_x{\mathrm{Se}}_{1-x}$ layers. We identify the Se vacancies $\left(V_{\mathrm{Se}}\right)$ in N-doped and the Zn vacancies $\left(V_{\mathrm{Zn}}\right)$ in Cl-doped material by the shape of the core electron momentum distribution. The charge of the defect involving $V_{\mathrm{Se}}$ is neutral or negative in $p-\mathrm{t}\mathrm{y}\mathrm{p}\mathrm{e}$ ${\mathrm{ZnS}}_x{\mathrm{Se}}_{1-x}$, suggesting that $V_{\mathrm{Se}}$ is complexed with an acceptor. The concentration of the $V_{\mathrm{Se}}$ complexes is high $(\ge {10}^{18}{\mathrm{cm}}^{-3\mathrm{}})$, indicating that their role is important in the electrical compensation of $p-\mathrm{t}\mathrm{y}\mathrm{p}\mathrm{e}$ ${\mathrm{ZnS}}_x{\mathrm{Se}}_{1-x}$.