Electric-field-induced quenching effect of photoluminescence on p-GaN films

The quenching and peak-shift effects of an external electric field on the Mg-related emissions of p-GaN films were investigated by using photoluminescence (PL) and photocurrent (PC) spectroscopy. The carriers generated by the Mg impurity centers in the p-GaN by PL excitation were found to be disturbed by the carriers excited by 325-mn line of light in the electric field. This disturbance reduces the direct recombination of the Mg-related carriers. Consequently, the quenching effect is associated with a decrease in the recombination of Mg-related carriers. In addition, the red shift of the PL peaks is related to the Stark effect induced by the external electric field. Moreover, diffraction experiments show that under an external electric field, the atoms in p-GaN are displaced small distances with a width of about 7.6 arcsec.