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Full-Text Articles in Engineering
Characteristics Of Free-Standing Hydride-Vapor-Phase-Epitaxy-Grown Gan With Very Low Defect Concentration, P. Visconti, K. M. Jones, Michael A. Reshchikov, F. Yun, R. Cingolani, Hadis Morkoç, S. S. Park, K. Y. Lee
Characteristics Of Free-Standing Hydride-Vapor-Phase-Epitaxy-Grown Gan With Very Low Defect Concentration, P. Visconti, K. M. Jones, Michael A. Reshchikov, F. Yun, R. Cingolani, Hadis Morkoç, S. S. Park, K. Y. Lee
Electrical and Computer Engineering Publications
A free-standing 300-μm-thick GaN template grown by hydride vapor phase epitaxy has been characterized for its structural and optical properties using x-ray diffraction, defect delineation etch followed by imaging with atomic force microscopy, and variable temperature photoluminescence. The Ga face and the N face of the c-plane GaN exhibited a wide variation in terms of the defect density. The defect concentrations on Ga and N faces were about 5×105 cm−2 for the former and about 1×107 cm−2 for the latter. The full width at half maximum of the symmetric (0002) x-ray diffraction peak was 69 and 160 arc sec …
Bias-Assisted Photoelectrochemical Etching Of P-Gan At 300 K, J. E. Borton, C. Cai, M. I. Nathan, P. Chow, J. M. Van Hove, A. Wowchak, Hadis Morkoç
Bias-Assisted Photoelectrochemical Etching Of P-Gan At 300 K, J. E. Borton, C. Cai, M. I. Nathan, P. Chow, J. M. Van Hove, A. Wowchak, Hadis Morkoç
Electrical and Computer Engineering Publications
Photoelectrochemical (PEC)etching of p-type GaN has been realized in room temperature, 0.1 M KOH solutions. PECetching of GaN was achieved by applying a positive bias to the surface of the p-GaN layer through a deposited titanium mask. The applied bias reduces the field at the semiconductor surface, which induced the dissolution of the GaN. The effect of bias on etch rate and morphology was examined. It was found that insulating the Ti mask from the KOH solution with Si3N4 significantly increases the etch rate. The rms roughness of the etched region decreased as the bias voltage increased. Etch rates …
Dislocation Density In Gan Determined By Photoelectrochemical And Hot-Wet Etching, P. Visconti, K. M. Jones, Michael A. Reshchikov, R. Cingolani, Hadis Morkoç, R. J. Molnar
Dislocation Density In Gan Determined By Photoelectrochemical And Hot-Wet Etching, P. Visconti, K. M. Jones, Michael A. Reshchikov, R. Cingolani, Hadis Morkoç, R. J. Molnar
Electrical and Computer Engineering Publications
Defects in GaN layers grown by hydride vapor-phase epitaxy have been investigated by photoelectrochemical (PEC)etching, and by wet etching in hot H3PO4acid and molten potassium hydroxide (KOH). Threading vertical wires (i.e., whiskers) and hexagonal-shaped etch pits are formed on the etched sample surfaces by PEC and wet etching, respectively. Using atomic-force microscopy, we find the density of “whisker-like” features to be 2×109 cm−2, the same value found for the etch-pit density on samples etched with both H3PO4 and molten KOH. This value is comparable to the dislocation density obtained in similar samples with tunnelingelectron microscopy, and is also consistent with …
Observation Of Electronic Raman Scattering From Mg-Doped Wurtzite Gan, K. T. Tsen, C. Koch, Y. Chen, Hadis Morkoç, J. Li, J. Y. Lin, H. X. Jiang
Observation Of Electronic Raman Scattering From Mg-Doped Wurtzite Gan, K. T. Tsen, C. Koch, Y. Chen, Hadis Morkoç, J. Li, J. Y. Lin, H. X. Jiang
Electrical and Computer Engineering Publications
Electronic Raman scattering experiments have been carried out on both molecular beam epitaxy and metal-organic chemical vapor deposition-grown Mg-doped wurtzite GaN samples. Aside from the expected Raman lines, a broad structure (full width at half maximum≅15 cm−1)observed at around 841 cm−1 is attributed to the electronic Raman scattering from neutral Mg impurities in Mg-doped GaN. Our experimental results demonstrate that the energy between the ground and first excited states of Mg impurities in wurtzite GaN is about one-half of its binding energy.
Well-Width Dependence Of The Ground Level Emission Of Gan/Algan Quantum Wells, A. Bonfiglio, M. Lomascolo, G. Traetta, R. Cingolani, A. Di Carlo, F. Della Sala, P. Lugli, A. Botchkarev, H. Morkoç
Well-Width Dependence Of The Ground Level Emission Of Gan/Algan Quantum Wells, A. Bonfiglio, M. Lomascolo, G. Traetta, R. Cingolani, A. Di Carlo, F. Della Sala, P. Lugli, A. Botchkarev, H. Morkoç
Electrical and Computer Engineering Publications
We have performed a systematic investigation of GaN/AlGaN quantum wells grown on different buffer layers (either GaN or AlGaN) in order to clarify the role of strain, structural parameters, and built-in field in determining the well-width dependence of the ground level emission energy. We find that identical quantum wells grown on different buffer layers exhibit strong variation of the ground level energy but similar well-width dependence. The data are quantitatively explained by an analytic model based on the envelope function formalism which accounts for screening and built-in field, and by a full self-consistent tight binding model.