Theoretical aspects and microstructural investigations on V-pit defects in HVPE grown GaN

Knetzger, Michael; Meissner, Η.; Schröter, Christopher; Friеdrich, J.

doi:10.1016/j.jcrysgro.2019.04.012

Cited by 4 publications

(3 citation statements)

References 27 publications

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“…5, it becomes clear why this region has a longer wavelength contribution in the spectrum and thus a redshift in the first moment mapping. In fact, it is possible to recognize V-pits [42], [43] (circled by a blue hexagonal line) and a trench-like defect (circled by a red line) [44]. The latter defect is found to originate from a stacking fault lying in the basal plane (BSF), which is connected to a vertical SMB terminating at the Vshaped trenches [45].…”

Section: Characterization and Discussionmentioning

confidence: 99%

V-Pits and Trench-Like Defects in High Periodicity MQWs GaN-Based Solar Cells: Extensive Electro-Optical Analysis

Nicoletto,

Caria,

Rampazzo

et al. 2024

IEEE Trans. Electron Devices

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By combining microscopy investigation, light-beam induced current (LBIC), microphotoluminescence (µ-PL), and micro-electroluminescence (µ-EL) characterization, we investigate the electrical and optical properties of V-pits and trench-like defects in highperiodicity InGaN/GaN multiple quantum wells (MQWs) solar cells. Experimental measurements indicate that V-pits and their complexes are preferential conductive paths under reverse and forward bias. Spectral analysis shows a redshifted wavelength contribution, with respect to MQWs emission peak wavelength, in presence of agglomerates of V-pits surrounded by trench-like defects. The intensity of the redshifted wavelength contribution Manuscript

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Section: Characterization and Discussionmentioning

confidence: 99%

V-Pits and Trench-Like Defects in High Periodicity MQWs GaN-Based Solar Cells: Extensive Electro-Optical Analysis

Nicoletto,

Caria,

Rampazzo

et al. 2024

IEEE Trans. Electron Devices

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“…The resulting scan is shown in Figure 3 a. The surface was mostly free of V-pits [ 18 , 19 ]; however, a high degree of step bunching [ 20 , 21 ] led to the formation of macrosteps of an average height of 13 nm, leading to a roughness

. Convinced that the macrosteps would needlessly complicate our reflectometry and ellipsometry measurements, we opted to remove about 15 nm of the layer with a silica-based chemical mechanical polishing (CMP) process, optimized to produce smooth surfaces ready for further epitaxial growth (similar to [ 22 ]).…”

Section: Methodsmentioning

confidence: 99%

Refractive Index of Heavily Germanium-Doped Gallium Nitride Measured by Spectral Reflectometry and Ellipsometry

et al. 2021

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Gallium nitride (GaN) doped with germanium at a level of 1020 cm−3 is proposed as a viable material for cladding layers in blue- and green-emitting laser diodes. Spectral reflectometry and ellipsometry are used to provide evidence of a reduced index of refraction in such layers. The refractive-index contrast to undoped GaN is about 0.990, which is comparable to undoped aluminium gallium nitride (AlGaN) with an aluminium composition of 6%. Germanium-doped GaN layers are lattice-matched to native GaN substrates; therefore, they introduce no strain, cracks, and wafer bowing. Their use, in place of strained AlGaN layers, will enable significant improvements to the production process yield.

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“…In MEI irradiation, both nuclear energy loss and electronic energy loss are comparable to each other and lead to combined effects or non-linear combined effects on damage production and damage recovery processes [15]. These effects of MEI irradiation lead to disorder build-up and microstructure expansion [16][17][18][19][20]. Studies on ion irradiation-induced effects in GaN semiconductor devices have been reported in the literature.…”

Section: Introductionmentioning

confidence: 99%

Medium Energy Carbon and Nitrogen Ion Beam Induced Modifications in Charge Transport, Structural and Optical Properties of Ni/Pd/n-GaN Schottky Barrier Diodes

et al. 2020

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The irradiation effects of carbon and nitrogen medium energy ions (MEI) on charge transport, structural and optical properties of Ni/Pd/n-GaN Schottky barrier diodes are reported. The devices are exposed to 600 keV C2+ and 650 keV N2+ ions in the fluence range of 1 × 1013 to 1 × 1015 ions cm−2. The SRIM/TRIM simulations provide quantitative estimations of damage created along the trajectories of ion beams in the device profile. The electrical parameters like Schottky barrier height, series resistance of the Ni/Pd/n-GaN Schottky barrier diodes decreases for a fluence of 1 × 1013 ions cm−2 and thereafter increases with an increase in fluence of 600 keV C2+ and 650 keV N2+ ions. The charge transport mechanism is influenced by various current transport mechanisms along with thermionic emission. Photoluminescence studies have demonstrated the presence of yellow luminescence in the pristine samples. It disappears at higher fluences due to the possible occupancy of Ga vacancies. The presence of the green luminescence band may be attributed to the dislocation caused by the combination of gallium vacancy clusters and impurities due to MEI irradiation. Furthermore, X-ray diffraction studies reveal that there is a decrease in the intensity and shift in the diffraction peaks towards the lower side of two thetas. The reductions in the intensity of C2+ ion irradiation is more when compared to N2+ ion irradiation, which may be attributed to change in the mean atomic scattering factor on a given site for light C2+ ion as compared to N2+ ion.

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Theoretical aspects and microstructural investigations on V-pit defects in HVPE grown GaN

Cited by 4 publications

References 27 publications

V-Pits and Trench-Like Defects in High Periodicity MQWs GaN-Based Solar Cells: Extensive Electro-Optical Analysis

V-Pits and Trench-Like Defects in High Periodicity MQWs GaN-Based Solar Cells: Extensive Electro-Optical Analysis

Refractive Index of Heavily Germanium-Doped Gallium Nitride Measured by Spectral Reflectometry and Ellipsometry

Medium Energy Carbon and Nitrogen Ion Beam Induced Modifications in Charge Transport, Structural and Optical Properties of Ni/Pd/n-GaN Schottky Barrier Diodes

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