Photoluminescence-based measurements of the energy gap and diffusion length of Zn3P2

The steady-state photoluminescence spectra of zinc phosphide (Zn3P2) wafers have revealed a fundamental indirect band gap at 1.38 eV, in close proximity to the direct band gap at 1.50 eV. These values are consistent with the values for the indirect and direct band gaps obtained from analysis of the complex dielectric function deduced from spectroscopic ellipsometric measurements. Bulk minority carrier lifetimes of 20 ns were observed by time-resolved photoluminescence decay measurements, implying minority-carrier diffusion lengths of >= 7 mu m. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3225151]