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RESEARCH PRODUCT

Residual strain effects on the two-dimensional electron gas concentration of AlGaN/GaN heterostructures

Martin StutzmannRoman DimitrovC. R. MiskysGema Martínez-criadoJoseph A. SmartOliver AmbacherAna CrosAndrés CantareroJames R. Shealy

subject

Electron densityTwo-dimensional electron gasMaterials sciencePhotoluminescenceIII-V semiconductorsAluminium compounds ; Gallium compounds ; III-V semiconductors ; Wide band gap semiconductors ; Semiconductor heterojunctions ; Two-dimensional electron gas ; Electron density ; Internal stresses ; Photoluminescence ; Raman spectra ; Excitons ; Interface states ; Piezoelectric semiconductors ; Dielectric polarisationExcitonAnalytical chemistryGeneral Physics and AstronomyDielectric polarisationMolecular physicsCondensed Matter::Materials Sciencesymbols.namesakeResidual stress:FÍSICA [UNESCO]Emission spectrumPiezoelectric semiconductorsPhotoluminescenceAluminium compoundsUNESCO::FÍSICAWide-bandgap semiconductorGallium compoundsHeterojunctionInterface statesWide band gap semiconductorssymbolsExcitonsRaman spectraSemiconductor heterojunctionsRaman spectroscopyInternal stressesElectron density

description

Ga-face AlGaN/GaN heterostructures with different sheet carrier concentrations have been studied by photoluminescence and Raman spectroscopy. Compared to bulk GaN, an energy shift of the excitonic emission lines towards higher energies was observed, indicating the presence of residual compressive strain in the GaN layer. This strain was confirmed by the shift of the E2 Raman line, from which biaxial compressive stresses ranging between 0.34 and 1.7 GPa were deduced. The spontaneous and piezoelectric polarizations for each layer of the heterostructures have been also calculated. The analysis of these quantities clarified the influence of the residual stress on the sheet electron concentration (ns). Possible causes for the discrepancies between the calculated and experimentally determined sheet carrier densities are briefly discussed. Andres.Cantarero@uv.es ; Gema.Martinez@uv.es

yearjournalcountryeditionlanguage
2001-11-01
10.1063/1.1408268http://hdl.handle.net/10550/13028