Band-edge luminescence degradation by low energy electron beam irradiation in GaN grown by metal-organic vapor phase epitaxy in H2 and N 2 ambients

The processing and characterization of optical components often requires the use of low energy electron beam (e-beam) techniques, such as scanning electron microscopy or electron beam lithography. The e-beam irradiation has been shown to produce band-edge luminescence degradation in GaN films grown by metal-organic vapor phase epitaxy (MOVPE), down to 20% of the original intensity in both photoluminescnece and cathodoluminescence measurements. The degradation is shown to be strongly related to activation of gallium vacancies in the GaN lattice. In this paper, this effect has been studied with GaN samples grown in two different carrier gases, N2 and H2. The degradation behavior appears almost identical in both cases, implying the vacancy formation to be independent of the carrier gas. Hence, MOVPE GaN electron beam irradiation resistance cannot be improved with the change of the carrier gas.