The temperature dependence of steady state photoluminescence(PL) is investigated for undoped and phosphorus-doped hydrogenated amorphous silicons. Plots of $\log(I_0/I-1)$ vs. T are obtained from experimental data, where I is PL intensity at temperature T and $I_0$ is a maximum PL intensity.
PL quenching mechanisms dominent in three temperature regions respectively are discussed. In low temperature region (←70℃K), an experimental law, $I_0/I-\infty T^{\gamma}$, is found, where γ is a sample dependent constant. In this temperature region, dominant PL quenching mechanism is due to a capture to defects occuring in diffusion during thermalization of electrons to demarcation level. In second temperature region, plots of $\log(I_0/I-1)$ vs. T show linearity. Dominant quenching mechanism is thermal ionization of electrons from band tail states. In third temperature region, the linearity does not hold any longer. All thermal ionized carriers are not nonradiatively captured to defects but a part of carriers recombine radiatively.
