Chinese Optics Letters, Vol. 7, Issue 3, 263 (2009)
Annealing induced refinement on optical transmission and electrical resistivity of indium tin oxide
Wei-Lun Hsu, Cheng-Tao Lin, Tzu-Huan Cheng, Shih-Chiang Yen, Chee-Wee Liu, Din Ping, and Gong-Ru Lin
- Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, No.1 Roosevelt Road Sec.4, Taipei 1062 Department of Physics, National Taiwan University, No.1 Roosevelt Road Sec.4, Taipei 106
The effect of annealing condition on sputtered indium tin oxide (ITO) films on quartz with the thickness of 200 nm is characterized to show enhanced optical transparency and optimized electrical contact resistivity. The as-deposited grown ITO film exhibits only 65% and 80% transmittance at 532 and 632.8 nm, respectively. After annealing at 475 oC for 15 min, the ITO film is refined to show improved transmittance at shorter wavelength region. The transmittances of 88.1% at 532 nm and 90.4% at 632.8 nm can be obtained. The 325-nm transmittance of the post-annealed ITO film is greatly increased from 12.7% to 41.9%. Optimized electrical property can be obtained when annealing below 450 oC, leading to a minimum sheet resistance of 26 \Omega/square. Such an ITO film with enhanced ultraviolet (UV) transmittance has become an alternative candidate for applications in current UV photonic devices. The morphology and conductance of the as-deposited and annealed ITO films are determined by using an atomic force microscopy (AFM), showing a great change on the uniformity distribution with finite improvement on the surface conductance of the ITO film after annealing.