Photoelectric properties of MSM structure based on ZnO nanorods, received by thermal evaporation and carbothermal syntesis

Abstract

Photoelectric characteristics of metal-semiconductor-metal (MSM) structures: Au/ZnO(nanorods)/ZnO(film)/ZnO(nanorods)/Au were investigated. Synthesis of ZnO nanorods (NR's) was carried out by two different methods, such as catalyst-free carbothermal synthesis (t &equal; 950°C, precursor – ZnO:C) and catalyst-free thermal evaporation of metallic Zn (t &equal; 600°C, precursor Zn). Photoluminescence spectra have shown that the ZnO NR's obtained by means of thermal evaporation technique have a lower concentration of point defects related with oxygen vacancies, than ZnO NR's prepared by carbothermal synthesis. MSM structure with ZnO NR's obtained by thermal evaporation technique have photosensitivity 97 mA/W at ~ 325 nm illumination and 44 mA/W at ~ 518 nm illumination at a bias 5V. For MSM structure with ZnO NR's obtained by method of carbothermal synthesis, the photosensitivity values were 22 mA/W, and 103 mA/W, respectively.