TY - JOUR

T1 - Density Functional Theory Calculations Revealing Metal-like Band Structures and Work Function Variation for Ultrathin Gallium Arsenide (111) Surface Layers

AU - Tan, Chih Shan

AU - Huang, Michael H.

PY - 2019/7/1

Y1 - 2019/7/1

N2 - Density functional theory (DFT) calculations have been performed on tunable numbers of gallium arsenide (100), (110), and (111) planes for their electron density of states (DOS) plots and the corresponding band diagrams. The GaAs (100) and (110) planes show the same semiconducting band structure with tunable plane layers and a band gap of 1.35 eV around the Fermi level. In contrast, metal-like band structures are obtained with a continuous band structure around the Fermi level for 1, 2, 4, 5, 7, and 8 layers of GaAs (111) planes. For 3, 6, and 9 GaAs (111) planes, the same semiconducting band structure as seen in the (100) and (110) planes returns. The results suggest the GaAs {111} face should be more electrically conductive than its {100} and {110} faces, due to the merged conduction band and valence band. GaAs (100) and (110) planes give a fixed work function, but the (111) planes have variable work function values that are smaller than that obtained for the (100) and (110) planes. Furthermore, bond length, bond geometry, and frontier orbital electron number and energy distribution show notable differences between the metal-like and semiconducting plane cases, so the emergence of plane-dependent electronic properties have quantum mechanical origin at the orbital level. GaAs should possess similar facet-dependent electronic properties to those of Si and Ge.

AB - Density functional theory (DFT) calculations have been performed on tunable numbers of gallium arsenide (100), (110), and (111) planes for their electron density of states (DOS) plots and the corresponding band diagrams. The GaAs (100) and (110) planes show the same semiconducting band structure with tunable plane layers and a band gap of 1.35 eV around the Fermi level. In contrast, metal-like band structures are obtained with a continuous band structure around the Fermi level for 1, 2, 4, 5, 7, and 8 layers of GaAs (111) planes. For 3, 6, and 9 GaAs (111) planes, the same semiconducting band structure as seen in the (100) and (110) planes returns. The results suggest the GaAs {111} face should be more electrically conductive than its {100} and {110} faces, due to the merged conduction band and valence band. GaAs (100) and (110) planes give a fixed work function, but the (111) planes have variable work function values that are smaller than that obtained for the (100) and (110) planes. Furthermore, bond length, bond geometry, and frontier orbital electron number and energy distribution show notable differences between the metal-like and semiconducting plane cases, so the emergence of plane-dependent electronic properties have quantum mechanical origin at the orbital level. GaAs should possess similar facet-dependent electronic properties to those of Si and Ge.

KW - density functional theory calculations

KW - density of states

KW - facet-dependent properties

KW - gallium arsenide

KW - semiconductors

UR - http://www.scopus.com/inward/record.url?scp=85067413841&partnerID=8YFLogxK

U2 - 10.1002/asia.201900597

DO - 10.1002/asia.201900597

M3 - Article

C2 - 31120175

AN - SCOPUS:85067413841

VL - 14

SP - 2316

EP - 2321

JO - Chemistry - An Asian Journal

JF - Chemistry - An Asian Journal

SN - 1861-4728

IS - 13

ER -