Temperature dependence of surface and bulk recombination in a-Si:H Schottky diodes

摘要

The photoconductivity of a-Si:H Schottky diodes has been studied as a function of illumination wavelength and intensity, applied electrical bias and temperature. The effect of temperature allowed us to separate two types of charge carrier losses with opposite temperature dependences. First the decrease of surface recombination with decreasing temperature is evidenced by the evolution of the spectral response and collection efficiency. Secondly, at low temperature, bulk recombination occurs when the light penetrates deeply into the diode, that is when the holes which have been generated in the bulk of the diode are trapped rather than collected. The experimental results are discussed in terms of the influence of the trapping of charge carriers on the electric field profile and collection efficiency.