ELECTRIC-FIELD EFFECTS ON EXCITONS IN GALLIUM NITRIDE

Electric-field effects on Wannier exciton are observed in GaN thin fil ms. Using both absorption and photocurrent measurements, we have studi ed the excitonic Franz-Keldysh effect in thin epitaxial GaN films at t emperatures between 80 and 300 K. We have measured the Stark shift, qu enching, and broadening of the exciton peak with applied field. These results are compared with theoretical calculations from the literature . The physics of exciton ionization at varying temperatures is discuss ed, which explains the interplay between absorption and photocurrent.