Terahertz photoconductivity of mobile electrons in nanoporous InP honeycombs

Nanostructured semiconductors with favorable optoelectronic properties can be created by electrochemical etching, a fabrication process that is scalable for mass market applications. Using terahertz photoconductivity measurements, we demonstrate that nanoporous InP has an unusually long carrier recombination lifetime that exceeds 100 ns at low temperatures and low carrier density, and an electron mobility half that of bulk InP. Modeling confirms that these observations result from band bending with holes confined to the surface and electrons away from the pores. © 2008 The American Physical Society

Photoconductive properties of HgGa2S4

Mercury thiogallate, HgGa2S4 is a defect chalcopyrite semiconductor with the space group S-4(2) which offers a combination of attractive properties for applications. In order to obtain information about the electron states in the energy gap, photoconductivity measurements are performed in the 80-300 K range. Photoconductivity spectra show two peaks related to intrinsic and extrinsic excitation at about 4 10 and 500 nm, respectively; these maxima show a temperature dependence similar to the linear coefficient of the energy gap. Thermally stimulated currents have been studied by exciting the samples with intrinsic light at different temperatures. For all excitation temperatures a single TSC peaks were obtained. The analysis of TSC curves allowed one to estimate the kinetics of the trap emptying, trap energy distribution and thermal activation energy. A model for the level distribution in the semiconductor energy gap is suggested which in good agreement with the results of a previous photoluminescence study. (C) 2003 Elsevier Ltd. All rights reserved

Temperature dependence of the photoluminescence spectra in AgGaS2

The Silver Gallium Sulfide (AgGaS2) ternary compound is a wide bandgap semiconductor (about 2.7 eV) whose photoluminescence properties are characterized by excitons and donor-acceptor pairs recombinations. We have performed photoluminescence (PL) measurement exciting with the third harmonic (3.5 eV) of a Nd:YAG laser from room temperature down to 10 K at different excitation power. In this work we report the dependence of the 'green band' on the excitation power at various temperatures. (c) 2005 Elsevier Ltd. All rights reserved