Carrier relaxation and recombination in an InGaN/GaN quantum well probed with time-resolved cathodoluminescence

Zhang, X.; Rich, D. H.; Kobayashi, J. T.; Kobayashi, Naoki; Dapkus, P.D.

doi:10.1063/1.121966

Cited by 46 publications

(45 citation statements)

References 13 publications

(13 reference statements)

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“…We note the values of , calculated in this work, are in agreement with the minority carrier lifetimes ͑1.4-2.3 ns͒, probed in InGaN/GaN quantum well, in situ in SEM, using time resolved cathodoluminescence. 11 In summary, the minority hole diffusion length in thick HVPE-grown GaN samples has been measured as a function of distance from the GaN/sapphire interface. We found a linear increase of L with increasing distance, which is in good agreement with an increase of the average distance between dislocations.…”

Section: Lϭͱd ͑1͒mentioning

confidence: 99%

Electron beam and optical depth profiling of quasibulk GaN

Chernyak

Osinsky

Nootz

et al. 2000

Applied Physics Letters

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Electron beam and optical depth profiling of thick (5.5–64 μm) quasibulk n-type GaN samples, grown by hydride vapor-phase epitaxy, were carried out using electron beam induced current (EBIC), microphotoluminescence (PL), and transmission electron microscopy (TEM). The minority carrier diffusion length, L, was found to increase linearly from 0.25 μm, at a distance of about 5 μm from the GaN/sapphire interface, to 0.63 μm at the GaN surface, for a 36-μm-thick sample. The increase in L was accompanied by a corresponding increase in PL band-to-band radiative transition intensity as a function of distance from the GaN/sapphire interface. We attribute the latter changes in PL intensity and minority carrier diffusion length to a reduced carrier mobility and lifetime at the interface, due to scattering at threading dislocations. The results of EBIC and PL measurements are in good agreement with the values for dislocation density obtained using TEM.

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Section: Lϭͱd ͑1͒mentioning

confidence: 99%

Electron beam and optical depth profiling of quasibulk GaN

Chernyak

Osinsky

Nootz

et al. 2000

Applied Physics Letters

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“…This can be attributed to band filling effects within the GaN due to the strong electron excitation of ∼800 pA at 7 kV. 23 Perpendicular to the NW axis, i.e., along a cross-section through the heterostructure, the emission is characterized by a constant signal in both energy and intensity. A slight attenuation toward the core−shell interface can be assigned to an effective decrease of excited core volume due to the cylindrical geometry of the core.…”

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confidence: 99%

Strain-Induced Band Gap Engineering in Selectively Grown GaN–(Al,Ga)N Core–Shell Nanowire Heterostructures

et al. 2016

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We demonstrate the selective area growth of GaN−(Al,Ga)N core−shell nanowire heterostructures directly on Si(111). Photoluminescence spectroscopy on as-grown nanowires reveals a strong blueshift of the GaN band gap from 3.40 to 3.64 eV at room temperature. Raman measurements relate this shift to compressive strain within the GaN core. On the nanoscale, cathodoluminescence spectroscopy and scanning transmission electron microscopy prove the homogeneity of strain-related luminescence along the nanowire axis and the absence of significant fluctuations within the shell, respectively. A comparison of the experimental findings with numerical simulations indicates the absence of a significant defect-related strain relaxation for all investigated structures, with a maximum compressive strain of −3.4% for a shell thickness of 50 nm. The accurate control of the nanowire dimensions, namely, core diameter, shell thickness, and nanowire period, via selective area growth allows a specific manipulation of the resulting strain within individual nanowires on the same sample. This, in turn, enables a spatially resolved adjustment of the GaN band gap with an energy range of 240 meV in a one-step growth process.

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“…The physical mechanism which stands behind this is not really known [3]. There are several possibilities that can be thought of: Carriers could be kept in randomly distributed potential minima within the quantum well, possibly caused by the inhomogeneity of In composition [4,5]. A second possibility is that the potential landscape is correlated with the defect positions, so that potential minima are formed somewhere between defects and keep carriers away from them.…”

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confidence: 99%

Correlation between Emission Spectra and Defect Position in InGaN‐Based Light Emitting Devices

Hitzel

Lahmann

Rossów

et al. 2002

phys. stat. sol. (c)

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PACS: 68.37. Uv; 68.55.Ln; 85.30.De GaN/InGaN/AlGaN devices grown on sapphire and SiC substrates have a high defect density due to a large lattice mismatch between substrate and active structure. Different models exist why defects are ineffective as recombination centres so that it is possible to manufacture high brightness InGaN-based LED devices despite the high defect density. Using a scanning near field optical microscope (SNOM) we were able to look at the emission spectra of GaInN/GaN multiple quantum wells in the vicinity of defects and to see the change of emission wavelength and light intensity around defect positions.

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Carrier relaxation and recombination in an InGaN/GaN quantum well probed with time-resolved cathodoluminescence

Cited by 46 publications

References 13 publications

Electron beam and optical depth profiling of quasibulk GaN

Electron beam and optical depth profiling of quasibulk GaN

Strain-Induced Band Gap Engineering in Selectively Grown GaN–(Al,Ga)N Core–Shell Nanowire Heterostructures

Correlation between Emission Spectra and Defect Position in InGaN‐Based Light Emitting Devices

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