Influence of internal electric fields on band gaps in short period GaN/GaAlN and InGaN/GaN polar superlattices

Gorczyca, I.; Skrobas, Kazimierz; Suski, T.; Christensen, N. E.; Svane, A.

doi:10.1063/1.4928613

Cited by 20 publications

(18 citation statements)

References 26 publications

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“…1(a) can be conserved upon overgrowth. 15 In a recent study of the carrier recombination dynamics in sample S 1/6 , no evidence for such an ordering was observed. On the contrary, the (In,Ga)N QSs were found to induce a spatially separate localization of electrons and holes analogous to conventional (In,Ga)N QWs.…”

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confidence: 94%

In/GaN(0001)-(3×3)R30° adsorbate structure as a template for embedded (In, Ga)N/GaN monolayers and short-period superlattices

Chèze

Feix

Anikeeva

et al. 2017

Applied Physics Letters

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We explore an alternative way to fabricate (In,Ga)N/GaN short-period superlattices on GaN(0001) by plasmaassisted molecular beam epitaxy. We exploit the existence of an In adsorbate structure manifesting itself by a ( √ 3 × √ 3)R30 • surface reconstruction observed in-situ by reflection high-energy electron diffraction. This In adlayer accommodates a maximum of 1/3 monolayer of In on the GaN surface and, under suitable conditions, can be embedded into GaN to form an In 0.33 Ga 0.67 N quantum sheet whose width is naturally limited to a single monolayer. Periodically inserting these quantum sheets, we synthesize (In,Ga)N/GaN short-period superlattices with abrupt interfaces and high periodicity as demonstrated by x-ray diffractometry and scanning transmission electron microscopy. The embedded quantum sheets are found to consist of single monolayers with an In content of 0.25-0.29. For a barrier thickness of 6 monolayers, the superlattice gives rise to a photoluminescence band at 3.16 eV, close to the theoretically predicted values for these structures.arXiv:1701.04680v1 [cond-mat.mtrl-sci]

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confidence: 94%

In/GaN(0001)-(3×3)R30° adsorbate structure as a template for embedded (In, Ga)N/GaN monolayers and short-period superlattices

Chèze

Feix

Anikeeva

et al. 2017

Applied Physics Letters

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“…16 Since this surface phase is self-limiting in thickness to a single ML and is laterally ordered, it may provide a template for the insertion of ordered InGa 2 N 3 QSs in GaN. 17 In this Letter, we study samples intentionally fabricated under conditions ensuring that the InN QSs are formed by this In adlayer and not by actual InN growth. We employ temperature-dependent photoluminescence (PL) spectroscopy under both continuous-wave (cw) and pulsed excitation to explore the electronic properties of these structures, which are found to be essentially indistinguishable from those reported in the literature for nominally full InN MLs embedded in GaN.…”

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confidence: 99%

Individual electron and hole localization in submonolayer InN quantum sheets embedded in GaN

Feix

Flissikowski

Chèze

et al. 2016

Applied Physics Letters

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We investigate sub-monolayer InN quantum sheets embedded in GaN(0001) by temperature-dependent photoluminescence spectroscopy under both continuous-wave and pulsed excitation. Both the peak energy and the linewidth of the emission band associated with the quantum sheets exhibit an anomalous dependence on temperature indicative of carrier localization. Photoluminescence transients reveal a power law decay at low temperatures reflecting that the recombining electrons and holes occupy spatially separate, individual potential minima reminiscent of conventional (In,Ga)N(0001) quantum wells exhibiting the characteristic disorder of a random alloy. At elevated temperatures, carrier delocalization sets in and is accompanied by a thermally activated quenching of the emission. We ascribe the strong nonradiative recombination to extended states in the GaN barriers and confirm our assumption by a simple rate-equation model.

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“…However, we can see from the comparison presented in ref. 13 that the agreement between estimated and ab-initio calculated values of E w and E b is quite satisfactory.…”

Section: Resultsmentioning

confidence: 62%

Band gap engineering of In(Ga)N/GaN short period superlattices

Gorczyca

Suski

Strąk

et al. 2017

Sci Rep

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Discussion of band gap behavior based on first principles calculations of the electronic band structures for several InN/GaN superlattices (SLs) (free-standing and pseudomorphic) grown along different directions (polar and nonpolar) is presented. Taking into account the dependence on internal strain and lattice geometry mainly two factors influence the dependence of the band gap, E g on the layer thickness: the internal electric field and the hyb wells) is more important. We also consider mIn ridization of well and barrier wave functions. We illustrate their influence on the band gap engineering by calculating the strength of built-in electric field and the oscillator strength. It appears that there are two interesting ranges of layer thicknesses. In one the influence of the electric field on the gaps is dominant (wider wells), whereas in the other the wave function hybridization (narrow wells) is more important. We also consider mIn0.33Ga0.67N/nGaN SLs, which seem to be easier to fabricate than high In content quantum wells. The calculated band gaps are compared with recent experimental data. It is shown that for In(Ga)N/GaN superlattices it is possible to exceed by far the range of band gap values, which can be realized in ternary InGaN alloys.

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Influence of internal electric fields on band gaps in short period GaN/GaAlN and InGaN/GaN polar superlattices

Cited by 20 publications

References 26 publications

In/GaN(0001)-(3×3)R30° adsorbate structure as a template for embedded (In, Ga)N/GaN monolayers and short-period superlattices

In/GaN(0001)-(3×3)R30° adsorbate structure as a template for embedded (In, Ga)N/GaN monolayers and short-period superlattices

Individual electron and hole localization in submonolayer InN quantum sheets embedded in GaN

Band gap engineering of In(Ga)N/GaN short period superlattices

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