ELECTRIC-FIELD QUENCHING OF CONTINUOUS-WAVE PHOTOLUMINESCENCE IN HYDROGENATED AMORPHOUS-SILICON

We have studied electric field quenching of continuous wave(CW) photol uminescence(PL) in device quality glow discharge deposited hydrogenate d amorphous silicon(a-Si:H). Electric fields in the range of 10(3) V/c m to 9x10(4) V/cm were used for these measurements. We find large quen ching of PL reaching almost 95% with the highest electric field at 100 K. The relative change in PL follows a power-law behavior with electr ic field with an exponent of 1.3 for fields below 6x10(4) V/cm and exh ibits a saturation for higher electric fields. Since a one dimensional Poole-Frenkel model fails to explain these results, we propose a pres ence of negatively charged shallow radiative centers with a temperatur e and electric field dependent hole capture cross-section in a-Si:H. W e also propose that the effect of these centers on PL quenching is dep endent on other factors such as defect density and doping.