Time-resolved spectroscopy of luminescence in Cu- and Cr-doped [beta]-Ga2O3

Time-resolved spectroscopy of photoluminescence has been studied in single-crystals of transition-metal doped [beta]-Ga2O3, particularly focusing on Cu- and Cr-doping effects on donor-acceptor recombination. Cr-doped [beta]-Ga2O3 still exhibits the photoluminescence due to the radiative recombination of donor-acceptor pairs but its temporal evolution is greatly suppressed, resulted from non-radiative decay channels through the d-d transitions in Cr3+ ions. The most of 3d transition metals give similar effects. On the other hand, in Cu-doped [beta]-Ga2O3 the luminescence spectrum and its temporal evolution are less sensitive to doping, reflecting no Cu-induced state inside of the band gap. The optical absorption spectrum also indicates that the most of 3d transition metals, except for Cu and Cr, greatly reduce the number of conducting carriers. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [PUBLICATION ABSTRACT]