Bandgap tunable Zn3-3xMg3xN2 alloy for earth-abundant solar absorber

Zn3-3xMg3xN2 alloy layers with x <= 0.3 can be epitaxially grown at a temperature as low as 140 degrees C. The bandgap (E-g) of Zn3-3xMg3xN2 widens from 1.2 to 2.5 eV with increasing x. The E-g value of 1.4 eV is obtained at x = 0.18, and the x = 0.18 film has a large absorption coefficient (10(4) - 10(5) cm(-1) ) in the visible region. The Zn3-3xMg3xN2 with E-g = 1.4 eV shows n-type conductivity with a reasonably high electron mobility of 47 cm(2) V-1 s(-1). Therefore, Zn3-3xMg3xN2 is a candidate for an earth-abundant solar absorber that can be fabricated at low temperatures. (C) 2018 Elsevier B.V. All rights reserved.