Thin films of pure nanocrystalline SnO₂ are deposited using sol–gel technique bare Si (100) substrates at different ageing time and annealing temperatures. The structural and morphological properties of these films are investigated using XRD and TEM techniques. The sensitivity of these films was tested to H₂ gas. A SnO₂ thin film aged for 7 h and annealed at 450 °C shows very high responses to H2 and excellent selectivity for H2 gas at a low operating temperature of 50 °C. The response and recovery time of SnO₂ thin films is discussed.

Keywords: Sol-Gel Method; Nanocrystalline SnO₂; Gas Sensor;