Free-carrier and phonon properties of<i>n</i>- and<i>p</i>-type hexagonal GaN films measured by infrared ellipsometry

Kasic, A.; Schubert, M.; Einfeldt, S.; Hommel, D.; Tiwald, Thomas E.

doi:10.1103/physrevb.62.7365

Cited by 252 publications

(221 citation statements)

References 68 publications

Supporting

Mentioning

201

Contrasting

Order By: Relevance

“…A value of the electron effective mass in GaN of 0.22 m 0 was taken. 40 The free electron concentrations in the GaN template and 50-nm-thick undoped InN buffer layer in the samples from set B were found to be 1.6 Â 10 17 cm À3 and 1.2 Â 10 19 cm À3 , respectively. The FCC parameters of the InN films are listed in Table I We found a systematic change of the FCC concentration with increasing Mg concentration in the InN films from set B similar to the results for set A.…”

Section: Resultsmentioning

confidence: 99%

“…39 The model dielectric functions of GaN and InN included contributions from lattice vibrations (phonons) and FCCs. 40,41 The uncoupled phonon mode parameters and the high-frequency limit of the dielectric function of GaN and InN are taken from our previous works. 40,42,43 The FCC contribution with consideration of longitudinal optical phonon plasmon coupling (LPP) was described by applying the Kukharskii model 29,44 e kð?Þ ðxÞ ¼ e 1;kð?…”

Section: Experimental and Data Analysismentioning

confidence: 99%

See 1 more Smart Citation

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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Experimental and Data Analysismentioning

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

Self Cite

View full text Add to dashboard Cite

show abstract

“…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. Anisotropic mobility parameters have been previously observed in GaN 18 and InN 11 and could be related to different distributions of extended defects and impurities in directions parallel and perpendicular to the c-axis. We further allowed for free-charge carriers in the SiC substrate and the AlN buffer layer, but no free-charge carrier contributions from these layers were revealed during the model analysis.…”

mentioning

confidence: 95%

“…17 Midinfrared spectroscopic ellipsometry (MIR-SE) in combination with electrical Hall effect measurements was previously applied by Kasic et al in order to investigate the phonon mode parameters and anisotropic effective mass parameter in GaN. 18 Slightly anisotropic effective electron mass parameters of m Ã k ¼ ð0:22860:008Þ m 0 parallel to the c-axis and m Ã ? ¼ ð0:23760:006Þ m 0 perpendicular to the c-axis were reported.…”

mentioning

confidence: 99%

“…Under the assumption of a linear increase of the effective mass parameter in AlGaN alloys with increasing Al-content and assuming an average effective mass value of m Ã ¼ 0:232 m 0 for electrons in GaN, 18 an average effective electron mass value of m Ã ¼ 0:376 m 0 can be extrapolated for AlN. The only experimental estimate of the effective electron mass parameter in AlN was given by Silveira et al 31 By analyzing cathodoluminescence measurements and using effective hole mass parameters in AlN as derived from the Mg acceptor binding energies in AlN 32 a range for the effective electron mass parameter of 0.28 m 0 to 0.45 m 0 was estimated.…”

mentioning

confidence: 99%

See 1 more Smart Citation

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

Schöche

Kühne

Hofmann

et al. 2013

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

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||

show abstract

Infrared Ellipsometry - a Novel Tool for Characterization of Group-III Nitride Heterostructures for Optoelectronic Device Applications

Schubert

Kasic

Einfeldt

et al. 2001

phys. stat. sol. (b)

Self Cite

View full text Add to dashboard Cite

We demonstrate the application of spectroscopic infrared ellipsometry to determine nondestructively the free-carrier distribution in group-III nitride heterostructures, such as for optoelectronic and electronic device applications. Results are shown for a blue-light emitting diode structure based on wurtzite III-N materials grown on (0001) sapphire by metal-organic vapor phase epitaxy.Success in growth of wide-band-gap group-III nitride alloys (Al, Ga, In)N over the past several years led to fast development of nitride-based semiconductor device research. In particular, the achievement of p-and n-type doping of respective device constituents resulted in production of short-wavelength light-emitting diodes (LEDs), laser diodes, and high temperature, high power, high frequency electronic devices. Control and characterization of doping profiles in complex heterostructures represents a challenge. Nondestructive and noninvasive tools are beneficial for both research and production environments.Polar lattice modes and absorption by free carriers (FC) dominate the infrared (ir) dielectric function (DF) of III-N compounds. Precise knowledge of the ir-DF provides fundamental material properties such as lattice phonon frequencies and broadening parameters, as well as mobility, concentration, and effective mass parameters of p-and n-type FCs. Ellipsometry for ir wavelengths can precisely determine the spectral dependence and anisotropy of a thin-film DF without the need for numerical Kramers-Kronig inversion, or reflectivity standards [1]. Advanced spectroscopic ellipsometry (SE) approaches allow differentiating between the optical responses of multiple layers within complex heterostructures [2]. SE approaches were recently progressed for determina-1

show abstract

Free-carrier and phonon properties ofn- andp-type hexagonal GaN films measured by infrared ellipsometry

Cited by 252 publications

References 68 publications

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

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

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

Infrared Ellipsometry - a Novel Tool for Characterization of Group-III Nitride Heterostructures for Optoelectronic Device Applications

Contact Info

Product

Resources

About