Thermally induced defect photoluminescence in hydrogenated amorphous silicon upon intense interband pumping

Abstract

Abstract An enhancement of defect photoluminescence (PL) intensity of amorphous hydrogenated silicon (a-Si:H) was discovered under powerful interband pumping leading to heating of the films of a-Si:H. The intensity of defect PL increases exponentially with temperature with an activation energy of 0.85 eV. The threshold intensity of pumping after which the sharp increase of defect PL intensity was observed to grow with decrease of the initial sample temperature. The explanation of these and the other experimental results of the spectroscopy and kinetics of PL of the a-Si:H is based on the thermally induced creation of defects (silicon dangling bonds). This defect creation is due to the establishment of quasi-thermodynamic equilibrium between the weak bonds and the dangling bonds.