Quantum size effects on the optical band gap of microcrystalline Si:H

Abstract

We have succeeded in fabricating the mostly crystallized Si:H materials having a wide optical band gap of up to 2.4 eV by means of a reactive sputtering technique with a low substrate temperature of \ensuremath{\sim}100 K. The structural analysis showed that the materials consist of small crystalline silicon particles surrounded by hydrogen atoms, whose diameters are 20--30 A\r{}. The widening of the optical band gap can be explained by a three-dimensional quantum-well effect in the small particles.