Increased photoluminescence of hydrogen-implanted ZnO thin films deposited using a pulsed laser deposition technique

Abstract

Low-energy (50keV) hydrogen implantation at a dose of 5×1012 ions/cm2 was performed on pulsed laser-deposited ZnO thin films. The films were subsequently rapid thermal annealed at 750°, 800, 850° and 900°C in ambient oxygen to remove any implantation-related defects. X-ray diffraction study confirmed deposition of highly c-axis-oriented 〈002〉 ZnO films in all of the samples. Hydrogen implantation did not have any effect on the carrier concentrations or Hall mobility of the samples. A low temperature photoluminescence study showed dominant donor-bound exciton peaks around 3.36eV along with a shoulder at 3.37eV corresponding to the free exciton peak for all of the samples. However, the integrated photoluminescence peak intensity revealed an enhanced intensity of the implanted sample (×4 times) and annealed samples (up to 100×) compared to the as-deposited sample. This enhanced luminescence from the hydrogen-implanted samples may be useful in fabricating highly efficient optoelectronic devices.