Growth and characterization of N-doped ZnS xSe 1− x (0 ≦ x < 0.3) by molecular beam epitaxy

Abstract

N-doped p-type ZnS x Se 1− x (0 ≦ x < 0.3) films were grown by molecular beam epitaxy (MBE) using radio-frequency (RF) plasma. The net acceptor concentration N a − N d decreased monotonically with increasing S composition and N a − N d of 2.5 × 10 17 cm −3 was achieved for the ZnS x Se 1− x film with S composition of 0.29, which has a bandgap energy of 3.0 eV at 77 K. The relative intensity of the I 1 peak (acceptor bound exciton) to DAP (donor-acceptor pair) emission increased with increasing S composition and the DAP emission became dominant with increasing temperature. From the temperature dependence of photoluminescence (PL) measurements, the activation energies of the N acceptor in ZnS x Se 1− x were estimated. The activation energy increased with increasing S composition and was comparable to that of ZnMgSSe.