Frequency-resolved photoluminescence spectroscopy of a-Si: H, a-P2Se, a-P3Se, and c-P4Se3

Abstract

Conventionally, frequency-resolved spectroscopy (FRS) measures the photo-luminescence (PL) intensity in exact quadrature to the modulated excitation and gives directly the lifetime distribution G(τ) of the PL over the time-scale 10⁻¹ to 10⁻⁶s. The first measurement of G(τ) for the midgap PL in a-P₂Se and c-P₄Se₃ has been obtained by this method. G(τ) is found to be extremely narrow for both glass and crystal; this is taken to be evidence for a common excitonic recombination mechanism.