Carrier Density Dependence of Optical Band Gap and Work Function in Sn-Doped In2O3 Films

Abstract

Carrier density dependence of the optical band gap and work function were investigated in undoped and Sn-doped In2O3 films. The optical band gap and the work function of the films showed clear positive and negative linear relationships, respectively, with two-thirds power of the carrier density. Optical band gaps increased from 3.8 to 4.3 eV when the carrier density increased from 8.8×1019 to 8.2×1020 cm-3, whereas work functions decreased from 5.5 to 4.8 eV. These variations could be attributed to the shift in the Fermi energy with varying carrier density in highly degenerated semiconductors.