Calcium as a nonradiative recombination center in InGaN

Calcium can be unintentionally incorporated during the growth of semiconductor devices. Using hybrid functional first-principles calculations, we assess the role of Ca impurities in GaN. Ca substituted on the cation site acts as a deep acceptor with a level similar to 1 eV above the GaN valence-band maximum. We find that for Ca concentrations of 10(17)cm(-3), the Shockley-Read-Hall recombination coefficient, A, of InGaN exceeds 10(6) s(-1) for band gaps less than 2.5 eV. A values of this magnitude can lead to significant reductions in the efficiency of light-emitting diodes. (C) 2017 The Japan Society of Applied Physics