Structural and Electronic Properties of Group V elements in Amorphous Semiconductors

Author(s)

Pedro Paulo de Mello Venezuela

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Física (IF/SBI)
• Defense date: 1996-12-18

Examining board members

Adalberto Fazzio; Alex Antonelli; Lucy Vitoria Credidio Assali; Hélio Chacham; Marcia Carvalho de Abreu Fantini

• Advisor: Adalberto Fazzio

Abstract

The electronic and structural properties of the elements N, P and AS in amorphous SI and GE are systematically investigated. The calculation procedure is based on two approaches. First, we have used the Monte Carlo method to generate the initial amorphous configurations. A reliable description of the atomic interaction is provided by using the Tersoff potentials. Having the initial model for the amorphous structure, we analyzed the electronic and structural configurations within the framework of the density-functional theory and the Bachelet-Hamann-Schlüter pseudopotentials. We found that the P and AS impurities are stable in 3-fold coordinated sites and metastable in 4-fold coordinated sites for both host systems. On the other hand, the N impurity presents a different behavior. This atom is stable in 3-fold coordinated sites for both host systems but in 4-fold coordinated sites it is unstable in a-SI and metastable in a-GE. The relevance of these results for the n-type doping in hydrogenated amorphous semiconductors is discussed. (AU)