Luminescence and recombine centre in ZnO/Si films

The D°h luminescence of ZnO films deposited on p-type Si substrates is produced by metal-organic chem-ical vapor deposition (MOCVD). After annealing in the air at 700°C for an hour, the photoluminescence (PL) spectra, the {itI-V} characteristics and the deep level transient spectro-scopy (DLTS) of the samples are measured. All the samples have a rectification characteristic. DLTS signals show two deep levels of {itE}{in1} and {itE}{in2}. The Gaussian fit curves of the PL spectra at room temperature show three luminescence lines {itb}, {itc} and {itd}, of which {itb} is attributed to the exciton emission. The donor level {itE}{in1} measured by DLTS and the location state donor ionization energy {itE}{ind} of the closely neighboring emission lines {itc} and {itd} are correlated. {itE}{in1} is judged as neutral donor bound to hole emission (D°h). Moreover, the intensity of the PL spectra decreases while the relative density of {itE}{in2} increases, showing that {itE}{in2} has the property of a non-radiative center.