Rapid thermal annealed Al-doped ZnO film for a UV detector

Abstract

A low-resistive Al-doped ZnO (AZO) film was achieved by rapid thermal annealing. A co-sputtering method was used in the initial growth of AZO films and a rapid annealing process was performed on the as-deposited AZO film under N 2 atmosphere for 3 min. An as-deposited AZO film had an optical transmittance of 84.78% at 550 nm and a resistivity of 7.8 × 10 − 3 Ω cm. A rapid annealing process significantly improved the optical transmittance and electrical resistivity of the AZO film to 99.67% and 1 × 10 − 3 Ω cm, respectively. The structural changes of the AZO films were investigated by X-ray diffraction and transmission electron microscopy. The high quality AZO film was used to fabricate a metal–semiconductor–metal (MSM) structure for a UV detector. The MSM device provided a stable current of 25 μA at a bias of 2 V in a dark condition. Under UV illumination, the MSM device was highly responsive to UV light uniformly and repeatedly, and it enhanced the current by 80% at 45 μA. This rapid thermal annealing process may provide a useful method to fabricate quality AZO films for photoelectric applications with a low thermal budget.