Cryogenic cathodoluminescence from Cu x Ag 1−x InSe 2 thin films

Cu x Ag 1−x InSe 2 (CAIS) thin films were deposited by a hybrid magnetron sputtering/evaporation process over a range of x values. Cryogenic cathodoluminescence (CL) data was obtained from these thin films. Emission peaks were identified and spectrally-resolved images were recorded at these wavelengths. A power-dependent CL series was also recorded. Emissions were fairly uniform across the sample for AgInSe 2 (AIS) (x=0). As x increased, the emission became less uniform both in intensity and in spectral components. AIS showed no significant difference between grain and grain boundary emission, while some grain boundaries in CAIS with x>0 showed higher emission intensity than the grains. No reduction in emission intensity was seen from topmost surface features in AIS, as opposed to CIS. Cu 0.6 Ag 0.4 InSe 2 showed the largest variation in emission from grain to grain, while CIS showed the largest variation in emission from grain to grain boundary.