Trace-level (20 ppm) H2S sensing characteristics of two sensor structures (i) bare SnO2 film (90 nm), and (ii) SnO2 film (90 nm) loaded with nanolayer (10 nm) of CuO catalyst, prepared using rf sputtering and pulsed laser deposition (PLD) have been investigated. H2S detection characteristics of bare SnO2 films is seen to get appreciably enhanced with the introduction of CuO nanolayer in case of both PLD (S similar to 147 to 2314) and rf sputtering (S similar to 14 to 211). Sensing hetero-structure grown using PLD exhibits good H2S detection characteristics with higher sensitivity (S similar to 2.3x10(3)) at a low operating temperature of 100 degrees C. (C) 2010 Elsevier B. V. All rights reserved.