Growth and characterization of cobalt oxide and copper doped cobalt oxide thin films prepared by reactive ion beam sputter deposition

• Main Authors: Po-Ta Ko, 柯伯達
• Other Authors: Liang-Chiun Chao
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/60287375506989162329

碩士 === 國立臺灣科技大學 === 電子工程系 === 104 === Cobalt oxide and copper doped cobalt oxide have been deposited by reactive ion beam sputter deposition. The effect of deposition temperatures and oxygen partial flow rates Opf (= O2/(O2+Ar)) on the properties of cobalt oxide and copper-cobalt oxide thin films were characterized. Experimental results show that cobalt oxide samples deposited at 150°C and 300°C are all Co3O4 and copper doped cobalt oxide samples result in the formation of CuCo2O4. As Opf increases, both XRD signal intensity drops, while the resistivity of Co3O4 and CuCo2O4 decrease as well. CuCo2O4 deposited at 300°C with Opf = 1.0 shows the lowest resistivity of 2.410-3 (·cm). The hole carrier concentration and mobility were estimated to be 9.721019 (cm-3) and 26.6 cm2 (Vs)-1, respectively. Hall measurement shows that both cobalt oxide and copper-cobalt oxide are all p-type semiconductor thin films. Co3O4 shows two band gap at ~1.4 and 2.0 eV, while CuCo2O4 shows only one direct band gap at 1.5~2 eV. The decrease in resistivity of CuCo2O4 is likely due to the presence of Cu that results in higher metal vacancy defects.