Influence of oxygen growth pressure on laser ablated Cr-doped In2O3 thin films
We present a systematic investigation of the effects of oxygen growth pressure on the structural, optical, and electrical properties of In2O3:Cr thin films grown by pulsed laser deposition. X-ray diffraction analysis showed increases in lattice constant from 10.103 Å to 10.337 Å, and in particle size from 13.9 nm to 35.5 nm as the oxygen growth pressure increased from 7.5 × 10-6 Torr to 7.5 × 10-3 Torr, respectively. The observed shift in the X-ray diffraction peaks to lower angles was assumed to be caused by the reduction in the lattice defect density, precisely oxygen vacancies. The optical transparency increased with partial oxygen pressure , and an average transmittance of ∼85% was obtained at 7.5 × 10-3 Torr. The films are highly conducting with resistivity as low as 2 × 10-4 Ω cm and mobility as high as 133 cm/V s. Temperature dependent resistivity measurements in the 45 < T < 300 K temperature range reveal that films grown at exhibit negative temperature coefficient of resistivity (TCR) below approximately T = 60 K, T = 120 K, T = 160 K; then positive TCR in the temperature intervals 60 < T < 300 K, 120 < T < 300 K, and 160 < T < 300 K, respectively. This suggests that two disparate mechanisms govern electrical dc transport in the two temperature regions. Film grown at of 7.5 × 10-3 Torr displayed typical semiconducting behavior with negative TCR in the whole temperature region.
Physics, Astronomy, and Materials Science
indium oxide, chromium, transparent conductor, mobility
Ukah, N. B., R. K. Gupta, P. K. Kahol, and K. Ghosh. "Influence of oxygen growth pressure on laser ablated Cr-doped In2O3 thin films." Applied surface science 255, no. 23 (2009): 9420-9424.
Applied surface science