Undoped ZnO nanostructures were deposited on SiO2/Si substrates via radio 11：equency magnetron sputtenng at different deposition temperatures （room temperature, 200, 300, and 400 ℃）. The prepared samples were anne...Undoped ZnO nanostructures were deposited on SiO2/Si substrates via radio 11：equency magnetron sputtenng at different deposition temperatures （room temperature, 200, 300, and 400 ℃）. The prepared samples were annealed at 500 ℃ for 2 h under an N2 flow. The structural, surface morphological, optical, and photoresponse characteristics of ZnO nanostructures as deposited and after annealing were then investigated. The energy bandgaps of all samples after annealing （3.22-3.28 eV） decreased compared with those of the as-deposited specimens. The barrier height increased when the deposition temperature increased and reached 0.77 eV at 400 ℃ after annealing with a leakage current of 0.17 gA at a 5 V bias. The UV photodetector device which was deposited at the optimal temperature of 300 ℃, has 12.51 × 10^3% pho- tosensitivity, 2.259 pA dark current, 0.508 s response time, and 0.466 s recovery time. The dark current significantly decreased for all samples after annealing. The proposed UV photodetectors exhibit high performance, high photosensi- tivity, shorter response and recovery times, and excellent stability at lower bias voltages of 5 and 2 V.展开更多
基金the funding provided by the Postgraduate Research Grant Scheme (PRGS) (Grant No. 1001/PFIZIK/845006) of the Universiti Sains Malaysia
文摘Undoped ZnO nanostructures were deposited on SiO2/Si substrates via radio 11：equency magnetron sputtenng at different deposition temperatures （room temperature, 200, 300, and 400 ℃）. The prepared samples were annealed at 500 ℃ for 2 h under an N2 flow. The structural, surface morphological, optical, and photoresponse characteristics of ZnO nanostructures as deposited and after annealing were then investigated. The energy bandgaps of all samples after annealing （3.22-3.28 eV） decreased compared with those of the as-deposited specimens. The barrier height increased when the deposition temperature increased and reached 0.77 eV at 400 ℃ after annealing with a leakage current of 0.17 gA at a 5 V bias. The UV photodetector device which was deposited at the optimal temperature of 300 ℃, has 12.51 × 10^3% pho- tosensitivity, 2.259 pA dark current, 0.508 s response time, and 0.466 s recovery time. The dark current significantly decreased for all samples after annealing. The proposed UV photodetectors exhibit high performance, high photosensi- tivity, shorter response and recovery times, and excellent stability at lower bias voltages of 5 and 2 V.
