Nitrogen doped ZnO thin films prepared by anode layer ion source reactive ion beam sputter deposition

• Main Authors: Han-chen Peng, 彭翰晨
• Other Authors: Liang-chiun Chao
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/qtya6e

碩士 === 國立臺灣科技大學 === 電子工程系 === 100 === Nitrogen doped ZnO (ZnO:N) thin films have been deposited by reactive ion beam sputter deposition utilizing an anode layer ion source. Both argon and nitrogen were passed simultaneously through the ion source to act as sputtering and reactive ion species, respectively. The plasma spectrum of the anode layer ion source shows distinctive atomic nitrogen emission lines suggesting that the incorporation of atomic nitrogen into ZnO may be improved. Experimental results show that all the film exhibit a preferred orientation along the (002) direction. A 20 nm un-doped ZnO was first deposited at 200?aC and subsequently annealed at 700?aC to act as buffer layers. Higher annealing temperature causes decomposition of the ZnO film and results in increased deep level green emission. ZnO:N was deposited on the buffer layer at 25 ~ 300?aC. Micro-Raman spectroscopy analysis shows Raman peaks at 275 and 582 cm-1, which is due to the local vibration mode of nitrogen in ZnO. All the nitrogen doped ZnO exhibit n-type conductivity. Conversion from n-type to p-type was not observed regardless of nitrogen flow rates or post-growth annealing. This is likely due to the formation of molecular nitrogen occupying oxygen sites (N2)O that act as double donors. Variable temperature Hall effect measurement shows that at temperatures above 165 K, the transport is governed by thermally activated carriers. The activation energy for conduction in this temperature range is 73 meV. The bandgap of ZnO:N is 3.158 eV, while the transmittance is larger than 80% in the visible region.