2 MeV proton radiation damage studies of gallium nitride films through low temperature photoluminescence spectroscopy measurements

This is the authors' abstract. We don't add key points for this paper.

Gallium nitride (GaN) thin film samples were grown by ammonia-molecular beam epitaxy. Through room temperature transport measurements, electron mobilities of 560 cm/sup 2//Vs were observed for layers with a carrier density of 1.5/spl times/10/sup 17/ cm/sup -3/. Room temperature photoluminescence (PL) spectroscopy revealed the bound exciton transition at 363.0 nm and a weak yellow emission whose intensity was sample dependent. At 22 K, the main photoluminescence signal sharpened, shifted to 356.9 nm (3.474 eV), and the maximum intensity increased by a factor of one hundred; the intensity of the yellow emission decreased. The samples were irradiated at room temperature with 2 MeV protons at fluences of 10/sup 9/, 10/sup 10/, 10/sup 11/, 10/sup 12/, 10/sup 13/, 10/sup 14/, 10/sup 15/, and 10/sup 16/ cm/sup -2/. The intensity changes were within experimental error up to 10/sup 13/ cm/sup -2/. The drop in intensity of the bound exciton transition was 16% at 10/sup 14/ cm/sup -2/ and 99% at 10/sup 15/ cm/sup -2/. The radiation damage constant associated with the main PL peak at 3.474 eV in GaN is (1.4/spl plusmn/0.3)/spl times/10/sup -13/ cm/sup 2/, compared with (4/spl plusmn/1)/spl times/10/sup -11/ cm/sup 2/ associated with the main PL, peak at 1.492 eV in GaAs. For photonic applications, GaN is more robust than GaAs with respect to displacement damage.