33 research outputs found
Dispersive photoluminescence decay by geminate recombination in amorphous semiconductors
The photoluminescence decay in amorphous semiconductors is described by power
law at long times. The power-law decay of photoluminescence at
long times is commonly observed but recent experiments have revealed that the
exponent, , is smaller than the value 1.5 predicted from a
geminate recombination model assuming normal diffusion. Transient currents
observed in the time-of-flight experiments are highly dispersive characterized
by the disorder parameter smaller than 1. Geminate recombination rate
should be influenced by the dispersive transport of charge carriers. In this
paper we derive the simple relation, . Not only the
exponent but also the amplitude of the decay calculated in this study is
consistent with measured photoluminescence in a-Si:H.Comment: 18pages. Submitted for the publication in Phys. Rev.
ISOTHERMAL CAPACITANCE TRANSIENT SPECTROSCOPY : ITS APPLICATION TO THE STUDY OF GAP STATES OF a-Si:H
A basic idea of ICTS (Isothermal Capacitance Transient Spectroscopy) for a system of continuously-distributed gap state and experimental data by the ICTS applied to P-doped a-Si:H Schottky barrier diode are presented. It is shown that the ICTS is a useful tool for the study of gap state of a-Si:H whose material parameters are strongly temperature-dependent
ANNEALING STUDIES ON LOW OPTICAL ABSORPTION OF GD a-Si:H USING PHOTOACOUSTIC SPECTROSCOPY
We have performed photoacoustic spectroscopy (PAS), ESR and ir absorption measurements on undoped GD a-Si:H film before and after isochronal annealings, from which absorption coefficient (down to α = 1 cm-1), spin density (Ns) and bonded H content (CH) were determined. It has been found out that the extraporated spectrum of spin-free a-Si:H shows a long exponential tail, and that additional broad absorption is strongly correlated with Ns. The origin of α below Eo is discussed