We use the post-transit photocurrent in a time-of-Night experiment for spectroscopic purposes. It is shown, within the multiple-trapping framework, that the post-transit current is the Laplace transform of the density of states. A simple inversion procedure is suggested and is shown to be quite adequate provided the gap-state distribution does not vary too strongly with energy. The method has been applied to hydrogenated amorphous silicon. Experimental evidence shows that the posttransit photocurrent truly rejects the release out of deeper-lying traps and is not a consequence of nonuniform, time-dependent fields, contact-related properties, or injection phenomena. The measured po~d are compatible with the deconvoluted density of states. A comparative discussion of our results with other published data obtained with conventional methods like the field-eff'ect, spacecharge-limited current, and deep-level transient spectroscopy techniques is given.
A preliminary investigation of the effects of doping arsenic triselenide with indium was carried out. Measurements of DC conductivity, photomobility and optical absorption were performed. We find a significant improvement in the main transport properties. The findings are explained in terms of a shift of the valence band edge towards the centre of the mobility gap as a function of doping rather than a shift of the Fermi level towards the band edge.
AbstracLDC conductivity, time of flight (mF) and Vansient photoconductivity (TP)measurements were performed in order to characterize samples of amorphous arsenic triselenide prepared by thermal evaporation. Analysis of the hole d e r drift mobility data provides strong evidence for carrier interaction with a s"cbxed distribution of defect centres rather than the broad featureless distribution that has in the past been proposed for arsenic uiselenide. Deviations from power law behaviour in the TP data also provide evidence for the existence of smctm. We applied the 'intuitive' thermalimion spectroscopic technique to the data and discovered defect centres situated at an energy position E1 -0.42 eV within the mobility gap.At high temperature the thermalization depth of holes is limited by a set of recombination centres sitnated,at El -0.65 eV above the valence band edge.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.