Electronic and optical properties of ScN and (Sc,Mn)N thin films deposited by reactive DC-magnetron sputtering
Date of this Version
8-14-2013Abstract
Scandium nitride (ScN) is a rocksalt semiconductor that has attracted significant attention from various researchers for a diverse range of applications. Motivated by the prospect of using its interesting electronic structure for optoelectronic and dilute magnetic semiconductor applications, we present detailed studies of the electronic transport and optical properties of ScN and its alloys with manganese nitride (MnN). Our results suggest (a) dilute manganese doping in ScN compensates for the high n-type carrier concentrations arising due to oxygen impurities and (b) an n-type to p-type carrier type transition occurs at a composition between 5.8% and 11% Mn on Sc sites. In terms of its optical properties, our analysis clearly indicates direct and indirect bandgap absorption edges of ScN located at 2.04 eV and 1.18 eV, respectively. In addition to the direct gap absorption edge, (Sc,Mn)N samples also show Mn-defect induced electronic absorption. Photoluminescence measurements at room temperature from ScN films exhibit a yellowish-green emission corresponding to direct gap radiative recombination. Direct gap recombination is not expected given the smaller indirect gap. A possible role of high excitation intensities in suppressing relaxation and recombination across the indirect bandgap is suspected. Raman spectroscopic and ellipsometric characterization of the dielectric permittivities of ScN and (Sc, Mn) N are also presented to assist in understanding the potential of ScN for optoelectronic applications. (C) 2013 AIP Publishing LLC.
Discipline(s)
Nanoscience and Nanotechnology
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Copyright 2013 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in J. Appl. Phys. 114, 063519 (2013); and may be found at http://scitation.aip.org/content/aip/journal/jap/114/6/10.1063/1.4817715. The following article has been submitted to/accepted by Journal of Applied Physics. Copyright 2013, Bivas Saha, Gururaj Naik, Vladimir P. Drachev, Alexandra Boltasseva, Ernesto E. Marinero and Timothy D. Sands. This article is distributed under a Creative Commons Attribution 3.0 Unported License.