Properties of ZnO:Al Films Prepared by Spin Coating of Aged Precursor Solution

• DOI: 10.5012/bkcs.2010.31.01.112
• Publication Date: 2010-04-13T06:10:12Z
• Authors: Shankar Prasad Sh...; Rishi Ghimire; Jeevan Jyoti Nakarmi; Young-Sung Kim; Sabita Shrestha; Chong-Yun Park; Jin-Hyo Boo
• Keywords: 01 natural sciences; 0104 chemical sciences

Transparent conducting undoped and Al impurity doped ZnO films were deposited on glass substrate by spin coat techni- que using 24 days aged ZnO precursor solution with solution of ethanol and diethanolamine. The films were charac- terized by UV-Visible spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), electrical resis- tivity (ρ), carrier concentration (n), and hall mobility (µ) measurements. XRD data show that the deposited film shows polycrystalline nature with hexagonal wurtzite structure with preferential orientation along (002) crystal plane. The SEM images show that surface morphology, porosity and grain sizes are affected by doping concentration. The Al doped samples show high transmittance and better resistivity. With increasing Al concentration only mild change in optical band gap is observed. Optical properties are not affected by aging of parent solution. A lowest resistivity (8.5 × 10 -2 ohm cm) is observed at 2 atomic percent (at.%) Al. With further increase in Al concentration, the resistivity started to increase significantly. The decrease resistivity with increasing Al concentration can be attributed to increase in both carrier concentration and hall mobility.