Epitaxial In2O3 layers for chemical sensors: structural and surface characterization

Abstract

Indium oxide is one of the basic oxides, which have been extensively studied [1-3] due to its prominent applications for gas sensor design, and as modeling material, possessed of some interesting chemical and structural peculiarities such as polar surfaces and systematic anion vacancies. Like conductometric gas sensor material it demonstrates enhanced sensitivity to oxidizing gases (O3, NO, etc.). During our own experiments the interesting and unusual effects concerned with surface and gas sensing properties of undoped In2O3 thin films were revealed [4-6]. Nevertheless of rather great efforts in the direction of basic understanding it can be stated the lack of generalized pattern in description of sensitivity mechanism on that oxide. Thorough study of fundamental sensing properties needs well-characterized surfaces like in single crystals or epitaxial layers. Thus we make an attempt to prepare and characterize epitaxial layers of In2O3 with (100) orientation. As it is known (100) plane is the most stable in the In2O3 crystal.