Ab initio study of energy band structures of GaAs nanoclusters

Abstract

Electronic states and optical transitions of hydrogen terminated GaAs nanoclusters up to 16.9 nm in diameter were studied using a large-scale quantum chemistry approach called central insertion scheme by which the quantum confinement effect is shown to quantitatively agree with experimental results. The ab initio study further reveals that the effective mass of the conduction-band electron (valence-band hole) in the GaAs nanocluster is larger (smaller) than the bulk material value.

Electronic Structure of Hydrogenated and Surface-Modified GaAs Nanocrystals: Ab Initio Calculations

“…However, the comparison with the gap of the fully optimized hydrogenated nanocrystal (9.57 eV) reveals that the energy gap reduction is very much more rapid than that observed for the lattice constant. In fact this fast reduction is supported by previous experimental and theoretical results [3]. All the calculated gaps in the present work for the two methods are blue shifted with respect to the bulk gap experimental value at 1.42 eV [1].…”

“…GaAs bulk or nanocrystals are excellent materials in many electronic devices [1][2][3][4]. The direct band gap of GaAs gives it superiority in light-emitting devices.…”

Structural and spectral properties of a non-classical C58 isomer and its fluorinated derivatives in theory

“…The simulated X-ray spectra also have been demonstrated to be effective for the determination of the electronic structures of many molecules, surfaces, clusters and bulk materials, such as DNAs, carbon nanotubes, fullerenes, etc. [59][60][61][62][63] The XES spectra have been performed by using the tool package BIONANO LEGO 64 at the B3LYP 42,43 /6-31G level with the group theory formulation developed by Luo et al 32,65 X-ray emission spectroscopy, which can provide information about the valence occupied orbitals, is composed of the radiative decay of valence electron into a core hole. Central insertion scheme (CIS) method 32,66 and a category of Krylov subspace methods 67 are applied to the BIONANO LEGO soware.…”

Role of surface ligands in optical properties of colloidal CdSe/CdS quantum dots

“…[2][3][4][5][6][7] This has motivated strong research efforts on QDs and their optical performance. For smaller QDs, more sophisticated approaches have been applied 8,9,14 to explore the band edge shifts and optical properties of the QDs with respect to the corresponding bulk materials. [8][9][10][11][12] Empirical relationships between QD size and absorption peak wavelength have been established experimentally, 10,11 and have been understood by solid-state electron-in-quantum-well models, e.g., using the effective mass approximation, 13 when the QD is relatively large.…”

“…[8][9][10][11][12] Empirical relationships between QD size and absorption peak wavelength have been established experimentally, 10,11 and have been understood by solid-state electron-in-quantum-well models, e.g., using the effective mass approximation, 13 when the QD is relatively large. For smaller QDs, more sophisticated approaches have been applied 8,9,14 to explore the band edge shifts and optical properties of the QDs with respect to the corresponding bulk materials.…”