Eka Nurfani, Grandprix T.M. Kadja, Muhammad A.K. Purbayanto, Yudi Darma
We have studied structural, electrical, and optical properties of ZnO thin films deposited by a spray technique. The samples were deposited by varying the deposition temperature from 200 °C (S200) up to 500 °C (S500). As the results, using X-ray diffraction and Raman scattering experiments, improvement in crystalline is observed by increasing the deposition temperature as indicated by the intensity enhancement of (002) plane and the E2-high vibration mode. From I–V curves, the photosensitivity of the films also increases up to 37 times (S500) with increasing the temperature. We reveal that strong UV absorption in S500 plays a significant role in the enhancement of sensitivity. On the other hand, the low dark current in S300 is due to the high density of oxygen vacancies, leading to higher mid-gap transitions, green emission, and Schottky barrier height. In the same time, the narrowing effect of the band gap from 3.28 to 3.20 eV is observed with the decrease of the temperature, which is related to the defect states from oxygen vacancies. Our study is essential to design and massively fabricate ZnO-based optoelectronic devices using a simple technique. © 2019 Elsevier B.V.
Materials Engineering Program, Institut Teknologi Sumatera, Terusan Ryacudu, Way Hui, Jati Agung, 35365, Lampung, Indonesia; Department of Chemistry, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Ganesha 10, Bandung, 40132, Indonesia; Research Center for Nanosciences and Nanotechnology, Institut Teknologi Bandung, Ganesha 10, Bandung, 40132, Indonesia; Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Ganesha 10, Bandung, 40132, Indonesia