Investigation of UV photoresponse property of Al, N co-doped ZnO film

• Al, N co-doped ZnO thin film prepared by sol–gel assisted spin coating method.
• P-type conductivity was confirmed from hall measurement.
• Nitrogen co-doping increased the photocurrent response and photocurrent gain.

Al, N co-doped zinc oxide thin films were prepared using sol–gel assisted spin coating method with a range of nitrogen (N) doping (x = 0, 1, 2). The deposited films were characterized through X-ray diffraction, UV–visible spectroscopy, photoluminescence spectroscopy and hall measurements to find structural, optical and electrical properties. The X-ray diffraction pattern was confirmed the existence of polycrystalline nature with wurtzite structure. The strong band emission and green emission peaks have been observed in Al, N co-doped films. The nitrogen undoped film demonstrated n-type conductivity and nitrogen doping brings p-type conductivity with maximum hole concentration of 8.111 × 1016 cm−3, carrier mobility of 9.965 cm2/V.s for higher nitrogen doped film (x = 2). The UV photo responsivity (7.17 × 10–5 A/W) and gain (724.36 × 10–5) of photo detector has been improved by a one order of magnitude in low nitrogen doping and decay time has been reduced drastically from 58.27 s to 10.32 s. These results demonstrated that the improved responsivity and decay time by 1 at% of nitrogen doping.