Influence of Sb incorporation on InGaAs(Sb)N/GaAs band alignment

Chang, Alexander S.; Zech, E.; Kim, Tae Wook; Lin, Yen-Hsiang; Mawst, Luke J.; Goldman, R. S.

doi:10.1063/1.4896781

Cited by 4 publications

(1 citation statement)

References 17 publications

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“…20,21 Moreover, GaSb and InSb have both been demonstrated to incorporate N and Bi effectively, resulting in a reduction in band gap [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] in a similar manner to the more widely studied, GaAs-based dilute nitrides and bismides. 39,40 Alloys can be produced of GaAs, GaSb and InSb, together with the relevant nitrides and/or bismides to tune the optical and electronic properties for a variety of applications; [41][42][43][44][45] indeed, very high efficiency tandem solar cells include an active layer composed of such an alloy. 46 Given the importance of GaSb and InSb, there are surprisingly few studies on their intrinsic defect properties, which are key to their dopability and hence functionality in devices.…”

Section: Introductionmentioning

confidence: 99%

Intrinsic point defects and the n - and p -type dopability of the narrow gap semiconductors GaSb and InSb

et al. 2019

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The presence of defects in the narrow-gap semiconductors GaSb and InSb affects their dopability and hence applicability for a range of optoelectronic applications. Here, we report hybrid density functional theory based calculations of the properties of intrinsic point defects in the two systems, including spin orbit coupling effects, which influence strongly their band structures. With the hybrid DFT approach we adopt, we obtain excellent agreement between our calculated band dispersions, structural, elastic and vibrational properties and available measurements. We compute point defect formation energies in both systems, finding that antisite disorder tends to dominate, apart from in GaSb under certain conditions, where cation vacancies can form in significant concentrations. Calculated self-consistent Fermi energies and equilibrium carrier and defect concentrations confirm the intrinsic n-and p-type behaviour of both materials under anion-rich and anion-poor conditions. Moreover, by computing the compensating defect concentrations due to the presence of ionised donors and acceptors, we explain the observed dopability of GaSb and InSb.

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Section: Introductionmentioning

confidence: 99%

Intrinsic point defects and the n - and p -type dopability of the narrow gap semiconductors GaSb and InSb

et al. 2019

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Formation and properties of InGaN QDs: Influence of substrates

Chang

Walrath

Frost

et al. 2019

Applied Physics Letters

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We examine the formation and properties of InGaN quantum dots (QDs) on free-standing GaN and GaN/sapphire templates, with and without buried InGaN/GaN QD superlattices (SLs). We use scanning tunneling microscopy (STM) and scanning tunneling spectroscopy to image the QDs and measure their electronic states. As the number of layers preceding the QDs increases (i.e., increasing substrate complexity), the total QD density increases. For free-standing GaN, STM reveals a mono-modal QD-size-distribution, consistent with a limited density of substrate threading dislocations serving as heterogeneous nucleation sites. For GaN/sapphire templates, STM reveals a bimodal QD-size-distribution, presumably due to the nucleation of additional ultra-small InN-rich QDs near threading dislocations. For multi-period QD SLs on GaN/sapphire templates, an ultra-high density of QDs, with a mono-modal size distribution is apparent, suggesting that QD nucleation is enhanced by preferential nucleation at strain energy minima directly above buried QDs. We discuss the relative influences of strain fields associated with threading dislocations and buried QD SLs on the formation of InGaN QDs and their effective bandgaps.

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