INFLUENCE OF WATER VAPORS AND HYDROGEN ON THE ENERGY BAND BENDING IN THE SnO2 MICROCRYSTALS OF POLYCRYSTALLINE TIN DIOXIDE FILMS

摘要

The results of studying the dependence of the energy band bending at the interface of contacting SnO2 microcrystals in the polycrystalline tin dioxide film on the humidity level of clean air and hydrogen concentration in the gas mixture of clean air + H-2 are presented. The experimental results showed that the bending of energy bands in SnO2 is decreased under exposure to the water vapors and molecular hydrogen. The presence of two types of the adsorption centers for water molecules on the surface of SnO2 is found. It is shown that at the absolute humidity of the gas mixture above 12 g/m(3), the H2O and H-2 molecules are adsorbed on the same centers, whose surface density is of 10(12) cm(-2) at a concentration of donor impurity in SnO2 equal to 10(18) cm(-3).