<title>SnO<formula><inf><roman>2</roman></inf></formula>:Sb transparent conducting coatings made by different sol-gel processes</title>

Abstract

Single and multilayer sot-gel coatings of transparent antimony-doped tin oxide (Sn02:Sb) have been prepared on borositicate and fused silica substrates using either a 5 mole% SbC13 doped 0.5 M solution of SnC12(OAc)2 in ethanol or a water suspension of crystalline Sb-doped tin oxide nanoparticles. The nanoscale morphology and the electrical parameters of the layers have been determined after different firing procedures and heating rates varying from 0.2 to 4300 K/s obtained either in a furnace or by cw CO2 laser irradiation. For a given sintering temperature (-540°C) a slow heating process in furnace leads to porous, homogeneous single and multilayers consisting of small crystallites. They present a high resistivity of about p = 4x 102 fcm. With increasing heating rate the layers become denser with larger crystallites and the resistivity value decrease down to 7x103 cm for 4300 K/s (CO2 laser sintering). It is proposed that the densification of the coatings is determined by a competition between nucleation at low temperatures and the growth ofthe crystatlites at high temperatures. 13,15,16] or Sb(OBu)3 [5,17,21], whereas fluorine doping has not yet been achieved by the sot-gel process. The use of sot stabilisers is only reported for a few solutions [13,15,16,22]. SnO2:Sb sol-gel coatings obtained until now present a relatively high resistivity, the lowest published value of p = 3x103 flcm [12], exceeding by more than one order of magnitude those obtained for coatings prepared by other methods (e.g. p 1x105 T1cm for Activated Reactive Evaporation of 5n02 and 5n02:Sb [25].