Dopant–dopant interactions in beryllium doped indium gallium arsenide: An ab initio study

Abstract

We present an ab initio study of dopant-dopant interactions in beryllium-doped InGaAs. We consider defect formation energies of various interstitial and substitutional defects and their combinations. We find that all substitutional-substitutional interactions can be neglected. On the other hand, interactions involving an interstitial defect are significant. Specially, interstitial Be is stabilized by about 0.9/1.0 eV in the presence of one/two BeGa substitutionals. Ga interstitial is also substantially stabilized by Be interstitials. Two Be interstitials can form a metastable Be-Be-Ga complex with a dissociation energy of 0.26 eV/Be. Therefore, interstitial defects and defectdefect interactions should be considered in accurate models of Be doped InGaAs. We suggest that In and Ga should be treated as separate atoms and not lumped into a single effective group III element, as has been done before. We identified dopant-centred states which indicate the presence of other charge states at finite temperatures, specifically, the presence of Beint +1 (as opposed to Beint +2 at 0K).

Detection of Be dopant pairing in VLS grown GaAs nanowires with twinning superlattices

“…Intriguingly, we find that ∼1% of Be atoms are found paired with another Be atom. The measured Be-Be radial distribution function (RDFs) is consistent with prior theoretical calculations [29] that predict formation of substitutional-interstitial pairs of Be dopants in GaAs. Our finding also agrees with a prior report of a defect complex including a Be interstitial in Be-doped GaAs nanowires characterized with Raman spectroscopy [30].…”

“…The frequency distribution analysis shown in table S1 also shows an excess of voxels containing two Be atoms. We attribute the observed excess to the presence of pairs of Be atoms, such as interstitial-substitutional pairs (Be i -Be Ga ), that have a low formation energy [29]. While the resolution of the RDF is, by inspection, sufficient to resolve the excess and deficit at ∼0.23 and ∼0.4 nm, respectively, the accuracy of the peak position is not sufficient to distinguish between distinct defect complexes involving substitutional and interstitial Be.…”

“…Spectroscopic signatures of Be dopant pairing have been reported for both Si [33] and GaAs [30]. Furthermore, first principles calculations predict that the formation of pairs of Be atoms in substitutional and interstitial sites (Be i -Be Ga ) with a net positive charge is energetically favorable in GaAs [29]. Although APT does not generally achieve the necessary spatial resolution to distinguish between substitutional and interstitial sites, it is feasible to analyze the atomic scale distribution of Be atoms to look for evidence of excess pairing that is theoretically predicted.…”

An investigation on the role of W doping in BiVO4 photoanodes used for solar water splitting

“…S2). 34 The formation energy shows that interstitial W is unlikely to happen due to its high formation energy. Thus, here we only calculated the defect formation energy of W replacing V. As seen from Fig.…”