Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5363361 | Applied Surface Science | 2011 | 5 Pages |
Titanium-doped indium oxide (ITiO) films were deposited on Corning glass 2000 substrates at room temperature by radio frequency magnetron sputtering followed by vacuum post-annealing. With increasing deposition power, the as-deposited films showed an increasingly crystalline nature. As-deposited amorphous ITiO films obtained at 20 W began to crystallize at the annealing temperature of 155 °C. Although there was no significant change in the crystalline structure of the films, electron mobility improved gradually with further increase in the annealing temperature. After post-annealing at 580 °C, the highest electron mobility of 50 cm2 Vâ1 sâ1 was obtained. Compared with the amorphous ITiO films, the ITiO films with a certain degree of crystallinity obtained at high deposition power were less affected by the vacuum annealing. Their electron mobility also improved due to post-annealing, but the increase was insignificant. After post-annealing, the optical transmission of the 325 nm-thick ITiO films showed approximately 80% at wavelengths ranging from 530 to 1100 nm, while the sheet resistance decreased to 10 Ω/sq. This makes them suitable for use as transparent conductive oxide layers of low bandgap solar cells.
⺠A new phenomenon in vacuum post-annealing ITiO films is presented. ⺠Post-annealing is more effective in improving electron mobility for amorphous ITiO film deposited at a lower power compared with crystallized ITiO films obtained at a higher power. ⺠ITiO film is suitable for use as window layers for solar cells with low bandgap absorbers.