Valley degeneracy in (110) Si quantum wells strain and misorientation effects

Author

Jiang, Zhengping B ; Kharche, Neerav ; Klimeck, Gerhard

Author_Institution

Network for Comput. Nanotechnol., Purdue Univ., West Lafayette, IN, USA

fYear

2010

fDate

26-29 Oct. 2010

Firstpage

1

Lastpage

4

Abstract

Valley degeneracy in (110) Si quantum wells (QWs) is studied. Band structures are computed using the nearest neighbor sp d s tight-binding model and strain relaxation is performed by a valence force field. Two degeneracy breaking mechanisms are identified: different confinement effective mass and valley-valley interaction. Strain and electric field are both found to enhance valley splitting. Surface miscuts towards [111] direction lift the 4 fold valley degeneracy of flat (110) QWs to 2 fold, which explains the experimentally observed inconsistency. Effects of surface miscut, which could only be addressed using an atomistic method, are included in the extended supercell calculation.

Keywords

conduction bands; effective mass; elemental semiconductors; semiconductor quantum wells; silicon; stress effects; tight-binding calculations; (110) Si quantum wells; 4 fold valley degeneracy; Si; atomistic method; band structure; confinement effective mass; degeneracy breaking mechanisms; extended supercell calculation; orientation effects; strain effects; strain relaxation; surface miscuts; tight-binding model; valence force field; valley splitting; valley-valley interaction; Effective mass; Electric fields; Lattices; Silicon; Silicon germanium; Solid modeling; Strain; miscut; strain; tight-binding; valley degeneracy; valley-valley interaction;

fLanguage

English

Publisher

ieee

Conference_Titel

Computational Electronics (IWCE), 2010 14th International Workshop on

Conference_Location

Pisa

Print_ISBN

978-1-4244-9383-8

Type

conf

DOI

10.1109/IWCE.2010.5677964

Filename

5677964