Band anticrossing effects in highly mismatched semiconductor alloys

a b s t r a c tThis work reports the effect of gamma (g-) irradiation on dilute GaAsN with nitrogen concentrations ranging from 0.2 to 1.2% with post-irradiation stability using CurrenteVoltage (IeV) and Deep Level Transient Spectroscopy (DLTS) measurements in the temperature range from 10 K to 450 K. The IeV results indicate that the irradiation effect was more pronounced in the samples with nitrogen concentration of 0.4%. Additionally, the irradiated samples showed an ideality factor higher than the as-grown samples. On the other hand, for temperatures above 265 K the barrier height of the irradiated samples with 0.8% nitrogen is higher than the as-grown samples. The DLTS measurements revealed that after irradiation the number of traps either decreased remained constant, or new traps are created depending on the concentration of nitrogen. For samples with N ¼ 0.2% e 0.4% the number of traps after irradiation decreased, whereas for samples with N ¼ 0.8% À 1.2 % the number of traps remained the same. However, the properties of some traps such as capture cross-sections and density increased by about 2 orders of magnitude. The origin of the defects present before and after irradiation are discussed and correlated.

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“…2 in Ref. [35]. While, the valence band (VB) maximum of this alloy is adjusted to zero and illustrated as a black solid line.…”

Section: Dlts and Laplace Dlts Characteristics Of As-grown And Irradimentioning

confidence: 99%

Investigation of the effects of gamma radiation on the electrical properties of dilute GaAs1−xNx layers grown by Molecular Beam Epitaxy

Saqri

Felix

Aziz

et al. 2015

Current Applied Physics

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“…To explain the composition dependence of the band gap in Ga(PAsN) the band anticrossing (BAC) model is very often utilized [20][21][22][23] . According to this model the interaction of dispersionless N-related states with conduction band states of Ga(PAs) host is modelled as a two-level system by the following Hamiltonian 1,32…”

Section: Introductionmentioning

confidence: 99%

Electronic band structure of nitrogen diluted Ga(PAsN): Formation of the intermediate band, direct and indirect optical transitions, and localization of states

Polak

Kudrawiec

Rubel

2019

Journal of Applied Physics

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The electronic band structure of Ga(PAsN) with a few percent of nitrogen is calculated in the whole composition of Ga(PAs) host using the state-of-the-art density functional methods including the modified Becke-Johnson functional to correctly reproduce the band gap, and band unfolding to reveal the character of the bands within the entire Brillouin zone. As expected, relatively small amounts of nitrogen introduced to Ga(PAs) lead to formation of an intermediate band below the conduction band which is consistent with the band anticrossing model, widely used to describe the electronic band structure of dilute nitrides. However, in this study calculations are performed in the whole Brillouin zone and reveal the significance of correct description of the band structure near the edges of Brillouin zone, especially for indirect band gap P-rich host alloy, which may not be properly captured with simpler models. The theoretical results are compared with experimental studies, confirming their reliability. The influence of nitrogen on the band structure is discussed in terms of application of Ga(PAsN) in optoelectronic devices such as intermediate band solar cells and light emitters. It is found that Ga(PAsN) with low N and As concentration has a band structure suitable for integration in Si tandem solar cells, since the lattice mismatch between Si and Ga(PAsN) is small in this case. Moreover, it is concluded that P-rich Ga(PAsN) alloys with low N concentration have a promising band structure for two colour emitters. Additionally, the effect of nitrogen incorporation on the carrier localization is studied and discussed.

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Band anticrossing effects in highly mismatched semiconductor alloys

Cited by 2 publications

References 28 publications

Investigation of the effects of gamma radiation on the electrical properties of dilute GaAs1−xNx layers grown by Molecular Beam Epitaxy

Investigation of the effects of gamma radiation on the electrical properties of dilute GaAs1−xNx layers grown by Molecular Beam Epitaxy

Electronic band structure of nitrogen diluted Ga(PAsN): Formation of the intermediate band, direct and indirect optical transitions, and localization of states

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