비정질 Ge의 광학적 성질

Abstract

The optical properties of amorphous Ge films (~1000~2000)Å have been studied in the near infrared range (1~2.5㎛). The optical constants are obtained from the analysis of simultaneous transmission data of two samples prepared exactly the same way but having slightly different thicknesses. The analysis is carried out in a self-consistent way by iteration. The results show fairly sharp absorption edge near 0.6 eV, the position of which depends on the sample thickness and the thermal treatment. The imaginary part of the dielectric constant can be fitted very well by assuming very small transition probabilities between localized states and by introducing energy-dependent transition matrix elments which are suitably adjusted to the density of states.