Effects of Thermal Annealing on Al-Doped ZnO Films Deposited on p-Type Gallium Nitride

C. J. Tun, J. K. Sheu, M. L. Lee, C. C. Hu, C. K. Hsieh, G. C. Chi
2006 Journal of the Electrochemical Society  
In this study, Al-doped ZnO ͑AZO͒ and Ni/AZO films were deposited on p-type GaN films followed by thermal annealing to form ohmic contacts. After thermal annealing, the resistivities of AZO films reduced from 5 ϫ 10 −3 to 4-6 ϫ 10 −4 ⍀ cm. Both as-deposited AZO and Ni/AZO contacts on p-GaN displayed a non-ohmic characteristic. Only the 800°C-annealed Ni/AZO contacts exhibited a linear current-voltage characteristic, showing a specific contact resistance of around 1.2 ϫ 10 −2 ⍀ cm 2 . After
more » ... ⍀ cm 2 . After undergoing the annealing in nitrogen ambience, the light transmittance of the Ni/AZO films increased from 70% to higher than 90% in the visible range. These results revealed that the Ni/AZO contact can serve as a suitable transparent current spreading layer for the fabrication of GaN-based light-emitting devices.
doi:10.1149/1.2171817 fatcat:3d5v2r6myzbu3j7w4iyad4ib7m