title: Electrical and optical characteristics of n-Zno/p-GaN hetero-junction diode fabricated by ultra-high vacuum sputter.
abstract: We investigated the electrical and optical properties of n-ZnO/p-GaN hetero-junction diode fabricated by an ultra-high vacuum radio frequency magnetron sputter. A physical relationship between the rotation rate during deposition process and post annealing conditions after deposited ZnO layer on p-GaN layer was discussed. When the rotation rates during deposition process of n-ZnO layer were 5 rpm and 15 rpm, the full width at half maximum of photoluminescence spectra of ZnO layer on the p-GaN layer was about 106 and 133 meV, respectively. Also, the ratio of deep level emission to near band edge emission was dramatically increased as increasing the rotation rate from 5 to 15 rpm. The n-ZnO/p-GaN hetero-junction diode grown at 5 rpm has a higher ratio of forward to reverse currents than the diode grown at 15 rpm. Also, the 600 degrees C-annealed diodes with 5 rpm showed good rectifying behavior with the barrier height of 0.74 eV, the ideality factor of 12.2, and the forward to reverse current ratio of 614 at +/- 8 V.
authors.affiliation: Quantum-Function Research Laboratory and Department of Physics, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Seong Gook
authors.initials: SG
authors.lastname: Cho
authors.forename: Dong Uk
authors.initials: DU
authors.lastname: Lee
authors.forename: Eun Kyu
authors.initials: EK
authors.lastname: Kim