Origin of visible light absorption in GaN-Rich (Ga1-xZnx)(N1-xOx) photocatalysts

Photoluminescence (PL) and photoluminescence excitation (PLE) spectra of (Ga1-xZnx)(N1-xOx) with compositions of x = 0.05-0.20 (i.e., GaN-rich) were measured at 10 K in an attempt to clarify the origin of the visible light activity of this material as a photocatalyst. It was found that the PL spectra of GaN-rich (Ga1-xZnx)(N1-xOx) can be interpreted to correspond to impurity levels, specifically acceptor levels formed by the substitution of Zn for Ga in GaN. The PL and PLE spectra suggest that the visible light absorption of this material occurs via the Zn-related acceptor levels.