Optical Hall Effect in Hexagonal InN

Hofmann, Tino; Darakchieva, Vanya; Ḿonemar, B.; Lu, Hai; Schaff, William J.; Schubert, M.

doi:10.1007/s11664-008-0385-8

Cited by 41 publications

(43 citation statements)

References 34 publications

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“…17 Our result for the sample of relatively high Al-content investigated here supports the theoretical predictions and is also in agreement with reports of vanishing effective mass anisotropy for similar electron concentrations in InN and GaN. 11 Slightly different mobility parameters of l ? ¼ ð3961Þ cm 2 /Vs and l k ¼ ð3261Þ cm 2 /Vs are determined for the directions perpendicular and parallel to the c-axis, respectively.…”

supporting

confidence: 90%

“…1,5,8 Prerequisite for OHE application is the existence of sufficiently high ($10 17 :::10 18 cm À3 ) free charge carrier concentration. Previous investigations on GaAs, 1,9 AlGaInP and BInGaAs alloys, 8 AlInP, 5 ZnMnSe, 4,10 InN, 4,6,11 AlGaN/GaN high-electron mobility structures, 7,12 and graphene 13 showed that the OHE provides accurate values of the effective mass parameter that corroborate the results found, for example, from Shubnikov-de Haas measurements. Achieving reliable n-type conductivity in high-Al-content AlGaN and AlN is very challenging due to the high ionization energy of the common donors (O and Si).…”

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confidence: 80%

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Electron effective mass in Al0.72Ga0.28N alloys determined by mid-infrared optical Hall effect

Schöche

Kühne

Hofmann

et al. 2013

Applied Physics Letters

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The effective electron mass parameter in Si-doped Al0.72Ga0.28N is determined to be m* = (0.336 +/- 0.020) m(0) from mid-infrared optical Hall effect measurements. No significant anisotropy of the effective electron mass parameter is found supporting theoretical predictions. Assuming a linear change of the effective electron mass with the Al content in AlGaN alloys and m* = 0.232m(0) for GaN, an average effective electron mass of m* = 0.376m(0) can be extrapolated for AlN. The analysis of mid-infrared spectroscopic ellipsometry measurements further confirms the two phonon mode behavior of the E-1(TO) and one phonon mode behavior of the A(1)(LO) phonon mode in high-Al-content AlGaN alloys as seen in previous Raman scattering studies.

Funding Agencies|National Science Foundation|MRSEC DMR-0820521MRI DMR-0922937DMR-0907475EPS-1004094|Swedish Research Council (VR)|2010-3848|Swedish Governmental Agency for Innovation Systems (VINNOVA)|2011-03486|Linkoping Linnaeus Initiative for Novel Functionalized Materials (VR)||VINNOVA||

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supporting

confidence: 90%

supporting

confidence: 80%

Electron effective mass in Al0.72Ga0.28N alloys determined by mid-infrared optical Hall effect

Schöche

Kühne

Hofmann

et al. 2013

Applied Physics Letters

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“…The dependence of the electron effective mass on carrier concentration reported in Ref. 49 was used for the InN n-type films, while in the case of free holes a constant hole effective mass of 0.42 m 0 in InN 25 was assumed. A value of the electron effective mass in GaN of 0.22 m 0 was taken.…”

Section: Resultsmentioning

confidence: 99%

Effect of Mg doping on the structural and free-charge carrier properties of InN films

Xie¹,

Sédrine²,

Schöche³

et al. 2014

Journal of Applied Physics

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We present a comprehensive study of free-charge carrier and structural properties of two sets of InN films grown by molecular beam epitaxy and systematically doped with Mg from 1.0 Â 10 18 cm À3 to 3.9 Â 10 21 cm À3 . The free electron and hole concentration, mobility, and plasmon broadening parameters are determined by infrared spectroscopic ellipsometry. The lattice parameters, microstructure, and surface morphology are determined by high-resolution X-ray diffraction and atomic force microscopy. Consistent results on the free-charge carrier type are found in the two sets of InN films and it is inferred that p-type conductivity could be achieved for 1.0 Â 10 18 cm À3 Շ [Mg] Շ 9.0 Â 10 19 cm À3 . The systematic change of free-charge carrier properties with Mg concentration is discussed in relation to the evolution of extended defect density and growth mode. A comparison between the structural characteristics and free electron concentrations in the films provides insights in the role of extended and point defects for the n-type conductivity in InN. It further allows to suggest pathways for achieving compensated InN material with relatively high electron mobility and low defect densities. The critical values of Mg concentration for which polarity inversion and formation of zinc-blende InN occurred are determined. Finally, the effect of Mg doping on the lattice parameters is established and different contributions to the strain in the films are discussed. V C 2014 AIP Publishing LLC.

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“…We note, however, that IRSE data on non-c-plane oriented samples and/or InN grown directly on sapphire as well as SE measurements in magnetic fields (OHE) provide enough sensitivity to determine the surface charge sheet density. 18,19,43 For the GaN template layer an electron concentration of 2:9 Â 10 17 cm À3 and a mobility of 102 cm 2 =Vs was obtained under assumption of an effective mass of 0:23 m 0 for GaN. 38 Using the dependence of the electron effective mass in InN on the carrier concentration as determined by OHE, 43 a buffer layer electron concentration of 1:1 Â 10 19 cm À3 and a mobility of 132 cm 2 =Vs were determined.…”

Section: Resultsmentioning

confidence: 99%

“…24,39 Further, parameters of free-charge carriers in different layers of a heterostructure can be determined individually. 24,43,44 Figure 3 shows the experimental and best-match model calculated data of OHE measurements performed on the undoped reference sample in the FIR spectral range at an angle of incidence of 72 . The differences of spectra taken at magnetic field strengths of þ1.5 T and À1.5 T for the off-diagonal Mueller-matrix elements MM 31 and MM 32 are shown.…”

Section: Resultsmentioning

confidence: 99%

Infrared to vacuum-ultraviolet ellipsometry and optical Hall-effect study of free-charge carrier parameters in Mg-doped InN

Schöche

Hofmann

Darakchieva

et al. 2013

Journal of Applied Physics

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Correlations between the morphology and emission properties of trench defects in InGaN/GaN quantum wells J. Appl. Phys. 113, 073505 (2013) Optical characterization of free electron concentration in heteroepitaxial InN layers using Fourier transform infrared spectroscopy and a 2×2 transfer-matrix algebra J. Appl. Phys. 113, 073502 (2013) Influence of structural anisotropy to anisotropic electron mobility in a-plane InN Appl. Phys. Lett. 102, 061904 (2013) Temperature dependent carrier dynamics in telecommunication band InAs quantum dots and dashes grown on InP substrates J. Appl. Phys. 113, 033506 (2013) Sub-250nm light emission and optical gain in AlGaN materials J. Appl. Phys. 113, 013106 (2013) Additional information on J. Appl. Phys. 19 cm À3 is indicated by the appearance of a dip structure in the infrared spectral region related to a loss in reflectivity of p-polarized light as a consequence of reduced LO phonon plasmon coupling, by vanishing free-charge carrier induced birefringence in the optical Hall-effect measurements, and by a sudden change in phonon-plasmon broadening behavior despite continuous change in the Mg concentration. By modeling the near-infrared-to-vacuum-ultraviolet ellipsometry data, information about layer thickness, electronic interband transitions, as well as surface roughness is extracted in dependence of the Mg concentration. A parameterized model that accounts for the phonon-plasmon coupling is applied for the infrared spectral range to determine the free-charge carrier concentration and mobility parameters in the doped bulk InN layer as well as the GaN template and undoped InN buffer layer. The optical Hall-effect best-match model parameters are consistent with those obtained from infrared ellipsometry analysis. V C 2013 American Institute of Physics. [http://dx

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Optical Hall Effect in Hexagonal InN

Cited by 41 publications

References 34 publications

Electron effective mass in Al0.72Ga0.28N alloys determined by mid-infrared optical Hall effect

Electron effective mass in Al0.72Ga0.28N alloys determined by mid-infrared optical Hall effect

Effect of Mg doping on the structural and free-charge carrier properties of InN films

Infrared to vacuum-ultraviolet ellipsometry and optical Hall-effect study of free-charge carrier parameters in Mg-doped InN

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