P-type nitrogen-doped ZnO thin films on sapphire (1 1 (2)over-bar-0) substrates by remote-plasma-enhanced metalorganic chemical vapor deposition

Nitrogen doped ZnO films were successfully grown, by remote-plasma-enhanced metalorganic chemical vapor deposition (RPE-MOCVD), having p-type conduction with carrier concentration ranging from 10(13) to 10(15) cm(-3) and resistivity of the order of 10(-1)-10(20) ohm cm. ZnO and ZnO:N films on sapphire substrate were characterized by Fourier transform infrared (FT-IR) and Raman spectroscopy (RS). Nitrogen-related RS modes emerged at 289, 587 and 653 cm(-1). Application of FT-IR for characterization, specially for films (ZnO and ZnO:N) deposited on a-plane sapphire was used as a new concept. IR modes of carbon-nitrogen complexes (CN, CC, and CO), NO and OH were observed. The complexes created in as-grown films were weakened due to annealing leading to change in conductivity to p-type. ZnO:N/ZnO (p-n) junctions were fabricated and rectifying I-V characteristics were obtained confirming attainment of p-type conduction. (c) 2006 Elsevier B.V. All rights reserved.