Realization of As-doped p-type ZnO thin films using sputter deposition

Arsenic-doped p-type ZnO (p-ZnO:As) thin films were deposited by the magnetron sputtering technique. High-resolution low-temperature photoluminescence (PL) spectra of the films revealed emissions at 3.35 eV and 3.32 eV, representing the neutral-acceptor-bound exciton transition and the free electron to acceptor level transition. Electroluminescence spectra of the p–n diodes fabricated from the p-ZnO:As/n-GaN heterostructure showed UV emission at about 380 nm and yellowish visible lights centered at 600–650 nm, which resembled the PL spectrum of the ZnO:As layer. The p-type ZnO films with 1at% As grown at 500°C showed a hole concentration of 5 × 1012–7 × 1013 cm−3 after the deposition and 4 × 1014–1 × 1016 cm−3 after annealing at 600 °C in oxygen atmosphere. High-resolution x-ray photoelectron spectroscopy indicated that most of the As dopants occupy Zn sites within the ZnO:As films.