Title :
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
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;
Conference_Titel :
Computational Electronics (IWCE), 2010 14th International Workshop on
Conference_Location :
Pisa
Print_ISBN :
978-1-4244-9383-8
DOI :
10.1109/IWCE.2010.5677964
