Influence of growth temperatures on the photoresponse of low temperature grown GaAs:As p-i-n diodes

We report a study of the sub-bandgap photoresponse of p-i-n photodetectors with 1 μm low-temperature intrinsic layers, and its dependence on the growth temperature of the intrinsic layer. Diodes with intrinsic layers grown near 250°C exhibit the highest photoresponse. The photoresponse decreases gradually as the growth temperature is raised above 250°C. For growth temperatures at or below 200°C, a drastic drop in the photoresponse is observed, along with degradation of crystal quality in the material. The extracted internal Schottky barrier heights are found to be within the range 0.7–0.8 eV.