Published online by Cambridge University Press: 17 March 2011
Illumination of hydrogenated amorphous silicon (a-Si:H) samples with short (e.g., 40 microsecond) pulses of red light produces a smaller metastable absorption increase in the defect region than continuous illumination of the same intensity for the same integrated exposure time. The defect absorption was measured at 1.3 and 1.4 eV by use of the constant photocurrent method (CPM). This smaller degradation is also observed in the photoconductivity. Careful measurement of the film temperature with several techniques confirm that the film temperature rises by less than 5 °C, under continuous illumination. However, several experiments suggest that the suppressed degradation during pulsed illumination is caused primarily by annealing during the dark time between pulses, even at 15 to 26 °C.