Hydrogen activated radiative states in GaAs/GaAlAs heterostructures and InGaAs/GaAs multiquantum wells

Abstract

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Near-Edge States Induced by Hydrogen Inclusion in Gallium Arsenide

“…The peak energies of those bands should be several tens of meV lower than the bandgap, depending on the NE states involved (see Table 1). As a matter of fact, PL bands have been observed (60 AE 5) meV below the bandgap in hydrogenated GaAs, AlGaAs, and InGaAs [2,3]. Those bands show also a fine structure which suggests the presence of several components in agreement with present estimates.…”

“…As a matter of fact, new structured bands have been reported a few tens of meV below the bandgap energy in the photoluminescence (PL) spectra of different hydrogenated III±V epilayers and heterostructures [2 to 4]. These bands are either unexplained [2], tentatively attributed to transitions involving localized levels which are associated to small local lattice deformations [3], or associated to H-plasma damage [4]. In the present work, local density functional calculations of equilibrium geometries, electronic charge distributions, and electronic eigenvalues are performed for different locations of neutral and charged H species in the GaAs lattice.…”

“…The localized orbitals used in the model (see Fig. 2) correspond to (i) the symmetric, bonding (BO) or antisymmetric, antibonding (AB) combination of two sp 3 hybridized atomic orbitals centered on the Ga and As atoms, respectively, and to (ii) the 1s atomic orbital of the H atom. The BO (+ +) orbital and the 1s (+) orbital lead to a bonding (+ + +) and to an antibonding (+ ± ± +) pair of new orbitals.…”

Exciton localization by potential fluctuations at the interface of InGaAs/GaAs quantum wells

“…It may also be worth mentioning here that near-edge states have been invoked to explain a PL band observed in hydrogenated bulk GaAs, from 50 to 90 meV below the GaAs band edge. 22 In that case, the insertion into the GaAs lattice of an H atom gives rise to a lattice deformation and to the insurgence of weak bonds, the possible origin of near-edge donorlike and acceptorlike states. In the present case, photogenerated carriers and weak bonds should give rise to donorlike and acceptorlike states localized at the interface where excitons ͑or electrons and holes͒ could be trapped.…”

Effect of hydrogen on modulation-doped AlGaAs/InGaAs/GaAs heterostructures: a photoluminescence study

“…It is well known that hydrogen in bulk samples as well as in quantum well (QW) structures saturate the dangling bond, passivates both shallow dopants and deep centers by forming hydrogen impurity complexes [1][2][3][4][5][6][7]. Gal et al [8] observed the neutralization of interface defects caused by misfit dislocations, in partially relaxed In y Ga 1Ky As/GaAs heterostructures by hydrogen plasma.…”