Growth and characteristics of ZnO thin film on CaF2 (11-21) substrate by metalorganic vapor phase epitaxy

摘要

Zinc oxide (ZnO) thin film was grown on CaF2 (11-21) substrate by metalorganic vapor phase epitaxy (MOVPE) and the structure, surface morphology and the opto-electrical properties of the film were investigated. It was found that preferential c-axis oriented ZnO film was highly transparent and quite smooth. In photoluminescence (PL) spectrum at 10 K, the neutral donor bound exciton ((DX)-X-0) emission was identified at 3.362 eV (I-4), the neutral acceptor bound exciton (A(0)X) emission at 3.346 eV (19). Free A- and B-exciton emissions at 3.374 eVand 3.386 eV, respectively, as well as the phonon replicas of free A-exciton and (DX)-X-0 were also observed, indicating high optical quality of the ZnO film. Temperature-dependent PL spectra demonstrated that the free exciton emission was dominant at a temperature larger than 215 K. Hall measurement showed that the ZnO/CaF2, film exhibited n-type conduction, with the resistivity of 114 Omega cm and the Hall mobility of 15.7 cm(2)/Vs. (c) 2004 Published by Elsevier B.V.