Band Structure Calculations of Strained Semiconductors Using Empirical Pseudopotential Theory

BAND STRUCTURE CALCULATIONS OF STRAINED SEMICONDUCTORS USING EMPIRICAL PSEUDOPOTENTIAL THEORY FEBRUARY 2011 JISEOK KIM B.S., KYUNGHEE UNIVERSITY SEOUL M.S., BALL STATE UNIVERSITY MUNCIE Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Massimo V. Fischetti Electronic band structure of various crystal orientations of relaxed and strained bulk, 1D and 2D confined semiconductors are investigated using nonlocal empirical pseudopotential method with spin-orbit interaction. For the bulk semiconductors, local and nonlocal pseudopotential parameters are obtained by fitting transportrelevant quantities, such as band gap, effective masses and deformation potentials, to available experimental data. A cubic-spline interpolation is used to extend local form factors to arbitrary q and the resulting transferable local pseudopotential V (q) with correct work function is used to investigate the 1D and 2D confined systems with supercell method. Quantum confinement, uniaxial and biaxial strain and crystal orientation effects of the band structure are investigated. Regarding the transport relavant quantities, we have found that the largest ballistic electron conductance ocvii curs for compressively-strained large-diameter [001] wires while the smallest transport electron effective mass is found for larger-diameter [110] wires under tensile stress.