Picosecond photoluminescence as a probe of band‐tail thermalization in a‐Si:H Available to Purchase

Recent picosecond time‐resolved photoluminescence measurements have obtained the initial decay dynamics in a‐Si:H over the range (10 psec‐4 nsec) in the high energy (>1.5 eV) part of the spectrum over a temperature range (T) from 20K to 180K at an excitation energy of 2.33 eV. The key features of the data are an initial unresolved decay (system response 10 psec) which evolves into an algebraic decay, t^−α, for 50 psec <t<3 nsec, with α(T)=α₀+βT. The onset of the power law occurs in a time range which is less than the fastest radiative lifetime. We interpret the results with a comprehensive model of nonradiative relaxation through electron band‐tail thermalization. Correlation between the thermalization process and radiative decay as well as T‐dependent local diffusion is discussed and shown to be in excellent agreement with the data.