Microstructure and Optoelectronic Properties of ZnCo2O4 Thin Films Prepared by Sol-Gel Processing

• Main Authors: ZHAM, MING-HAN, 詹明翰
• Other Authors: YU, RUEI-SUNG
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/ezrjx2

碩士 === 亞洲大學 === 光電與通訊學系 === 106 === In this study, the effects of amorphous Zn-Co-O and spinel ZnCo2O4 on the photoelectric properties were investigated. The film was annealed at 250 °C to form a single crystallite ZnCo2O4. Annealing temperature was higher than 350 °C to enhance the crystallinity. ZnCo2O4 film had nano-grain, and the surface morphology was polygonal with irregular shaped. With the annealing temperatures increase, which the films’ nano-grain and polygonal microstructure sizes increase. The root mean square value of the amorphous Zn-Co-O film was 0.58 nm, and the RMS values of the ZnCo2O4 film annealed between 250 and 600 °C were 0.65~7.34 nm. The light transmittance has a red-shift phenomenon. Absorption coefficient curve of the spinel ZnCo2O4 film exhibits a characteristic absorption peak at about 400 nm, and the absorption peak becomes more obvious with the increasing of crystallinity. The ZnCo2O4 film had band gaps between 4.14 and 4.19 eV. Analytical composition of Zn, Co and O was 14.35: 27.65: 57.99 at%, which was in accordance with the ZnCo2O4 chemical formula of 1:2:4. The film annealed at 300 °C had the lowest resistivity of 8.22 Ω-cm, and also had the highest carrier concentration of 2.98 x 1018 cm-3, and the energy gap value was 4.14 eV.