Light‐induced effects on the radiative recombination rate of electron‐hole pairs in a‐Si:H

Abstract

Temperature variation of radiative recombination rate obtained for defect photoluminescence (PL) in high‐quality a‐Si:H after illumination of intense pulsed light is presented and compared with results previously reported for defective a‐Si:H films. We have not found significant difference between the temperature variation of the rate of radiative recombination at photo‐created radiative defects and that at native radiative defects. This fact suggests the recombination processes at the photo‐created defects and the native defects are similar. The temperature dependence of the radiative recombination rates in a‐Si:H is predicted by a model of the recombination processes for various cases of different density of deep and strongly localised tail states. Our recent experimental results for the principal PL and defect PL coincide with the prediction of the model. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Thermal quenching of defect photoluminescence and recombination rates of electron–hole pairs in a-Si:H

“…2(a) shows the non-radiative recombination rates estimated by Eqs. (2) and (3) with τ R0 = 0.69 ms. The same results are shown as logP NR vs. T − 1 plots in Fig.…”

“…1 clearly show that P R increases so quickly that P NR /P R decreases with increasing temperature in the range of 120-170 K in the case of HQ1. We have proposed a model [2] in which P R above 100 K increases because of thermal excitation of the holes to shallow tail states extended more than deep tail states. Such an increase of P R is significant when the density of the deep tail states is small [2].…”

“…We have proposed a model [2] in which P R above 100 K increases because of thermal excitation of the holes to shallow tail states extended more than deep tail states. Such an increase of P R is significant when the density of the deep tail states is small [2]. High density of photo-created dangling-bonds of Si may give rise to more disordered network and high density of strongly localized deep tail states.…”

“…thermal quenching, has been interpreted [1] assuming that the non-radiative recombination rate has an activation-type temperature dependence and the radiative recombination rate is independent of the temperature. However, our recent studies indicate that the radiative recombination rate strongly depends on the temperature [2]. The temperature dependence of the radiative recombination rate has been well understood by considering the thermal excitation of the carriers at the tail states and self-trapping of the holes at low temperatures [2].…”

“…However, our recent studies indicate that the radiative recombination rate strongly depends on the temperature [2]. The temperature dependence of the radiative recombination rate has been well understood by considering the thermal excitation of the carriers at the tail states and self-trapping of the holes at low temperatures [2].…”