Defect-related optical transitions in GaN

Rieger, W.; Dimitrov, R.; Brunner, Daniel; Rohrer, E.P.; Ambacher, O.; Stutzmann, M.

doi:10.1103/physrevb.54.17596

Cited by 88 publications

(63 citation statements)

References 30 publications

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“…Later films, grown with the nitrogen filter, show no evidence of this line, thus supporting its interpretation as arising from oxygen (O). The set of lines centered near 3.35 eV have been associated with stacking faults (SF) near the GaN/SiC interface [23]. Figure 10 shows the effect of substrate preparation on the spectra.…”

Section: Optical Characterizationmentioning

confidence: 99%

Properties of GaN epitaxial layers grown on 6H-SiC(0001) by plasma-assisted molecular beam epitaxy

Lee

Vidhya

Sagar

et al. 2001

Journal of Elec Materi

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The structural, electrical, and optical properties of GaN grown on 6H-SiC(0001) substrates by molecular beam epitaxy are studied. Suitable substrate preparation and growth conditions are found to greatly improve the structural quality of the films. Threading dislocation densities of about 1 × 10 9 cm -2 for edge dislocations and < 1 × 10 6 cm -2 for screw dislocations are achieved in GaN films of 0.8 µm thickness. Mechanisms of dislocation generation and annihilation are discussed. Increasing the Ga to N flux ratio used during growth is found to improve the surface morphology. An unintentional electron concentration in the films of about 5 × 10 17 cm -3 is observed, and is attributed to excess Si in the films due to a Si-cleaning step used in the substrate preparation. Results from optical characterization are correlated with the structural and electronic studies.

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Section: Optical Characterizationmentioning

confidence: 99%

Properties of GaN epitaxial layers grown on 6H-SiC(0001) by plasma-assisted molecular beam epitaxy

Lee

Vidhya

Sagar

et al. 2001

Journal of Elec Materi

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“…The nature of these lines has been frequently discussed in the recent literature on GaN [17] [18], however, there is no satisfactory explanation of their origin. Attempts have been made to attribute these lines to localized excitons in wurtzite GaN [18], to the shallow bound exciton in the cubic GaN [17], and recently to quantum confined states in cubic inclusions in GaN [19]. Similar features have also been observed in materials apparently containing no GaN at all.…”

Section: Resultsmentioning

confidence: 64%

Optical Properties of GaNAs Grown by MBE

Pozina

Ivanov

Ḿonemar

et al. 1998

MRS Internet j. nitride semicond. res.

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Optical properties of the GaNxAs1−x layers grown on (001) GaAs substrates by molecular beam epitaxy have been studied. The samples can be classified into three categories with respect to the concentration of N, as determined by x-ray diffraction and secondary-ion mass spectrometry: (i) with doping nitrogen concentration, (ii) with average content of N less than 30 %, and (iii) with x close to 100 %. From optical measurements of photoluminescence and Raman scattering, combined with analysis of x-ray diffraction spectra, different phases are observed in the GaNxAs1−x layers: GaAs, GaN and the solid ternary solution GaNxAs1−x. We have estimated the fundamental band-gap energy in the GaNxAs1−x alloy with low nitrogen concentration (up to x = 0.04) from absorption measurements, and in GaNxAs1−x with low arsenic concentration (up to 1−x = 0.04) - from photoluminescence spectra. An analysis of the dependence of the experimental values of the GaNxAs1−x band-gap energy on the nitrogen composition indicates a constant bowing parameter b as large as b = -18 eV.

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“…Above 90 K, both holes and electrons delocalized, and the transition energy follows the thermally induced band gap shrinking. This phenomenon may relate to the high density stacking faults in the m-plane GaN layer, which is similar to those of c-plane 17 and a-plane GaN with high density stacking faults. 18 Theoretical calculations predict that the stacking faults will induce a conduction band offset of about 220-270 meV.…”

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confidence: 98%

Polarization and temperature dependence of photoluminescence of m-plane GaN grown on γ-LiAlO2 (100) substrate

Liu

Kong

Zhang

et al. 2009

Applied Physics Letters

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We investigated the polarization and temperature dependence of photoluminescence ͑PL͒ of m-plane GaN grown on ␥-LiAlO 2 ͑100͒ substrate. The calculated electronic band structure with k • p Hamiltonian points out the energy splitting as well as polarization selection originate from the m-plane GaN epilayer under anisotropic strain. The polarization-angle dependence PL spectra are found to be selected from in-plane x-and z-polarized emission, corresponding to T 1 and T 2 transition. And the intensity distribution of the fitting peaks satisfies the Malus' law. An S-shape energy evolution of near band edge peak on temperatures is observed, which originates from the transition between the localized holes and electrons in triangular potentials induced by basal stacking faults. © 2009 American Institute of Physics. ͓DOI: 10.1063/1.3204453͔ Spontaneous and piezoelectric polarization along the ͓0001͔ axis of wurtzite GaN and its alloys greatly affect the efficiency of luminescence in GaN-based optoelectronic devices. 1 In order to eliminate these polarization effects, one way is to deposit an m-or a-plane GaN film along unconventional non-polar directions, such as ͓1100͔ ͑Ref. 2-4͒ or ͓1120͔. 5-7 ␥-LiAlO 2 ͑LAO͒ has a tetragonal structure and its ͑100͒ plane exhibits a comparatively small lattice mismatch to GaN ͑1100͒. Since the m-plane GaN was grown by molecular-beam epitaxy on this substrate, 2 the development of nonpolar GaN based optoelectronic devices has attracted much attention. Unlike c-plane GaN, nonpolar GaN usually suffers from anisotropic in-plane strain, which leads to a splitting in the electronic band structure ͑EBS͒. Therefore, understanding the EBS of nonpolar GaN is significant for the application of optoelectronic devices. Previously, optical measurements, such as reflectance, transmission, and photoreflectance, were used to determine the EBS near the ⌫ point and verify the theoretical calculation of the energy splitting of the m-plane GaN. [8][9][10][11] Luminescence properties of a-plane GaN, including temperature and polarization dependent, spatially resolved photoluminescence ͑PL͒ and cathodoluminescence, were also particularly studied. [12][13][14] Recently, the authors reported the splitting and anisotropy of emission light polarization of the m-plane GaN on LAO͑100͒ by using PL measurements. 15 In this letter, we investigate the polarization-angle and temperature dependence of the polarized PL transitions of the m-plane GaN film on LAO͑100͒ in order to explore the evolution of splitting valence band under anisotropic strain conditions.The studied sample of a typical 0.92 m thick m-plane GaN with background electron concentration ϳ2 ϫ 10 18 cm −3 ͑named as sample I͒ was grown on LAO͑100͒ by metalorganic chemical vapor deposition. 4 High-resolution x-ray diffraction technique revealed the m-plane GaN epilayer under biaxial compressive strain of xx = −0.79% and zz = −0.14% with an out-of-plane dilatation yy = 0.38%. 15 An unintentionally doped n-type c-plane GaN with thickness of 2.5 m on ␣-Al 2 O...

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Defect-related optical transitions in GaN

Cited by 88 publications

References 30 publications

Properties of GaN epitaxial layers grown on 6H-SiC(0001) by plasma-assisted molecular beam epitaxy

Properties of GaN epitaxial layers grown on 6H-SiC(0001) by plasma-assisted molecular beam epitaxy

Optical Properties of GaNAs Grown by MBE

Polarization and temperature dependence of photoluminescence of m-plane GaN grown on γ-LiAlO2 (100) substrate

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