Ab initiocluster calculations of hydrogenated GaAs(001) surfaces

Abstract

Hydrogen adsorption on the ͑2ϫ4͒ and ͑4ϫ2͒ reconstructions of gallium arsenide ͑001͒ has been studied by internal reflectance infrared spectroscopy and ab initio cluster calculations with density-functional theory. The calculations are made on Ga 5 As 4 H 11,13 , Ga 4 As 5 H 11,13 , and Ga 7 As 8 H 19 clusters, which model the arsenic-and gallium-dimer termination of the semiconductor surface. Excellent agreement has been achieved between the vibrational frequencies predicted by the theory and those observed in experiments. On the ͑2ϫ4͒, hydrogen adsorbs on arsenic dimers to form isolated and coupled arsenic-monohydrogen bonds, and arsenic-dihydrogen bonds. Conversely, on the ͑4ϫ2͒, hydrogen adsorbs on gallium dimers to form terminal and bridged gallium hydrides. The latter species occur in isolated or coupled structures involving two or three Ga atoms.

Hydrogen adsorption on phosphorus-rich(2×1)indium phosphide (001)

“…19,21,39 We estimate that this should decrease by about fourfold the intensity of the modes perpendicular to the surface, which are the symmetric vibrations of the coupled H-P-P-H and PH 2 species. This may explain the weak intensity of the mode at 2317 cm Ϫ1 .…”

“…19 However, this is unsatisfactory and leads to unphysical bridging hydrides in bulk atom positions. In this work, the truncated dative bonds at bulk indium atoms are replaced by dative bonds to PH 3 groups.…”

“…11,16 -21 Definitive assignments of the M -H vibrational modes is accomplished by building cluster models of the adsorption sites and then optimizing the cluster structure using ab initio calculations with density functional theory ͑DFT͒. [19][20][21][22][23][24][25][26][27] Over the past several years, we have been studying the atomic structure of indium phosphide ͑001͒ surfaces produced by metalorganic vapor-phase epitaxy ͑MOVPE͒. 11,28 -30 The most stable phosphorus-rich reconstruction is (2ϫ1), which consists of a single monolayer of phosphorus dimers.…”

Red shift in the photoluminescence of indium gallium arsenide nitride induced by annealing in nitrogen trifluoride

“…This allows NF 3 to adsorb onto the unoccupied group V sites. During the course of annealing, arsenic continues to desorb, providing a pathway for arsenic to diffuse out of the bulk film, following a vacancy diffusion mechanism [21]. Nitrogen atoms at the surface can then diffuse into the bulk, making use of bulk group V vacancies.…”

Feedback control of surface roughness of GaAs [001] thin films using kinetic Monte-Carlo models

“…Gallium arsenide (GaAs) is an important compound semiconductor that has many applications including light-emitting diodes, microwave devices, broadband communications, and space solar cells (Fu, Li, & Hicks, 2000). The GaAs thin films can be deposited by either molecular-beam epitaxy (MBE) (e.g., Vanhove, Lent, Pukite, & Cohen, 1983) or metal-organic chemical vapor deposition (MOCVD) (e.g., Tirtowidjojo & Pollard, 1988;Law, Li, Begarney, & Hicks, 2000).…”