Effect of laser irradiation on the properties of indium tin oxide films deposited by pulsed laser deposition

High quality indium tin oxide (ITO) firms of thickness 80 +/- 20 nm grown b y laser irradiation of the glass substrates during pulsed laser deposition are reported. Films were deposited from a 5 wt.% SnO2-doped In2O3 target at substrate temperatures (T,) ranging from room temperature (RT) to 400 degr eesC and oxygen pressure (PO2) of 1.3 Pa. The energy of the laser beam focu sed unto the middle of the glass substrate during coatings was about 70 mJ cm(-2). The structural, electrical and optical properties of the laser-irra diated and the nonirradiated parts of the ITO films were studied as a funct ion of T-s. Crystalline films with (I I I) preferred orientation and crysta l sizes much greater than 200 nm were obtained at all T-s. At RT, the resis tivity of the laser-irradiated part of one him was 1.2 x 10(-4) Ohm cm comp ared with 2.3 x 10(-4) Ohm cm for a nonirradiated part. At 300 degreesC, a low resistivity value of 8.5 x 10(-5) Ohm cm was achieved for both the lase r-irradiated and the nonirradiated parts of the ITO film. The achievement o f low resistivity resulted from the high carrier concentration similar to 1 .2 x 10(21) cm(-3) and the high Hall mobility (40-57) cm(2) V-1 s(-1). The films also exhibited high optical transmittance (similar to 90%) to visible light. (C) 2001 Elsevier Science B.V, All rights reserved.