Photoluminescence characteristics of AlGaN-GaN-AlGaN quantum wells

Khan, M. Asif; Skogman, R. A.; Hove, J. M. Van; Krishnankutty, S.; Kolbas, R. M.

doi:10.1063/1.102530

Cited by 116 publications

(27 citation statements)

References 6 publications

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“…In Al x Ga 1Àx N, the band gap increases from 3.4 to 6.2 eV, 22 about 65% of the band gap difference is accommodated in the conduction band (up shift) and 35% in the valence band (down shift). 23 Thus, an Al-content of around x ¼ 0.2 will be sufficient to align the conduction bands in Cu 2 O and Al x Ga 1Àx N. For such small Al-contents, the electrical properties of the films are still excellent and easily controllable. 24 For Cu 2 O on ZnO, the conduction band offset is 0.97 eV.…”

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confidence: 99%

The band alignment of Cu2O/ZnO and Cu2O/GaN heterostructures

Kramm

Läufer

Reppin

et al. 2012

Applied Physics Letters

100

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Using photoelectron spectroscopy, we investigate the band alignments of the Cu2O/ZnO heterointerface and compare the findings with the corresponding values for Cu2O/GaN. While for Cu2O/ZnO, we find a valence band offset (VBO) of 2.17 eV and a conduction band offset (CBO) of 0.97 eV, both values are considerably reduced for Cu2O/GaN where the numbers are 1.47 eV (VBO) and 0.24 eV (CBO), respectively. The large CBO between ZnO and Cu2O will very likely result in low photovoltaic power conversion efficiencies as is the current status of Cu2O/ZnO solar cells.

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confidence: 99%

The band alignment of Cu2O/ZnO and Cu2O/GaN heterostructures

Kramm

Läufer

Reppin

et al. 2012

Applied Physics Letters

100

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“…3,4 Quantum wells ͑QWs͒ have been the device structure of choice for efficient III-nitride semiconductor based light emitters. 5,6 Conventional nitride c-plane multiple QW structures generate fixed sheet charges at the interfaces due to the spontaneous and piezoelectric polarization. [7][8][9][10] which induce internal electric fields, lead to carrier separation, and reduce the radiative recombination rate.…”

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confidence: 99%

Photoluminescence properties of AlN homoepilayers with different orientations

Sedhain

Nepal

Nakarmi

et al. 2008

Applied Physics Letters

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AlN homoepilayers and heteroepilayers were grown on polar c-plane and nonpolar a-plane and m-plane orientations of AlN bulk and sapphire substrates by metal organic chemical vapor deposition. A systematic comparative study of photoluminescence properties of these samples revealed that all AlN homoepilayers ͑c, a and m planes͒ were strain free with an identical band gap of about 6.099 ͑6.035͒ eV at 10 ͑300͒ K, which is about 42 meV below the band gap of c-plane AlN heteroepilayers grown on sapphire. Also, nonpolar a-plane homoepilayers have the highest emission intensity over all other types of epilayers. We believe that a-plane AlN homoepilayers have the potential to provide orders of magnitude improvement in the performance of new generation deep UV photonic devices. © 2008 American Institute of Physics. ͓DOI: 10.1063/1.2965613͔ AlN has a complete solid solubility with GaN ͑Ref. 1͒ and emerged as an important semiconductor material for applications of light emitters down to 200 nm ͑Ref. 2͒ and detectors in the deep ultraviolet ͑DUV͒ and extreme UV spectral region. 3,4 Quantum wells ͑QWs͒ have been the device structure of choice for efficient III-nitride semiconductor based light emitters. 5,6 Conventional nitride c-plane multiple QW structures generate fixed sheet charges at the interfaces due to the spontaneous and piezoelectric polarization. 7-10 which induce internal electric fields, lead to carrier separation, and reduce the radiative recombination rate. Consequently, optoelectronic devices such as light emitting diodes and laser diodes based on heteroepitaxial c-plane oriented III-nitride materials possess reduced internal quantum efficiencies.There has been tremendous effort in the investigation of nonpolar a-plane and m-plane III-nitride epilayers 11 and optoelectronic devices with QW structures 9,10 to reduce the effects of internal electric fields. To achieve QW and other heterostructure based devices with improved performance, optical properties of epilayers grown on different orientations of available substrates have to be better understood. Furthermore, most previous studies on the fundamental band structures of AlN have been carried out for heteroepilayers grown on sapphires, which are plagued by lattice mismatch induced strain and high threading dislocation density, which significantly inhibited our ability for precisely determining the fundamental band structure parameters of AlN. In this work, we report a systematic comparative study of optical properties of both homoepitaxial and heteroepitaxial layers of AlN grown on polar c-plane as well as a-plane and m-plane orientations probed by DUV photoluminescence ͑PL͒.AlN bulk single crystal substrates were produced by sublimation crystal growth using polycrystalline AlN wafer as seeds and have a thickness of about 1 mm and an average grain size of about 2 ϫ 3 mm 2 . 12 The surface of AlN bulk crystal substrates was prepared by chemical mechanical polishing ͑done by NovaSiC͒ that provided a surface roughness of about 1 -4 nm. The dislocation density i...

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“…Values as high as 1500 cm2/Vs at room temperature have been achieved in the authors' laboratory (Wu, et al 1996). The optical properties of AlGaN/GaN quantum wells (Kahn, et al 1990) were found to be determined by both, quantum and strain related effects Krishnankutty, et al 1992b). MOCVD A1N films showed a full width of half maximum of the (002) x-ray rocking curve peak as low as 97 arcseconds (Saxler, et al 1994).…”

Section: Growth Of Algan and Algan/gan Heterostructuresmentioning

confidence: 99%

High-Temperature Electronics in Europe

Dmitriev¹,

Chow²,

DenBaars³

et al. 2000

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Support is provided by a variety of U.S. government agencies, including ONR, DoC, and NSF.ITRI's mission is two-pronged: (1) to inform U.S. policymakers, strategic planners, and managers of the state of selected technologies in foreign countries in comparison to the United States; and (2) to identify opportunities for international cooperation among countries and collaboration among researchers. ITRI assessments cover basic research, advanced development, and applications. Panels of typically six technical experts conduct these assessments. Panelists are leading authorities in their fields, technically active, and knowledgeable about U.S. and foreign research programs. As part of the assessment process, panels visit and carry out extensive discussions with foreign scientists and engineers in their labs.The ITRI staff at Loyola College helps select topics, recruits expert panelists, arranges study visits to foreign laboratories, organizes workshop presentations, and finally, edits and disseminates the final reports. HIGH-TEMPERATURE ELECTRONICS IN EUROPE August 2000Vladimir Dmitriev (Chair) T. Paul Chow Steven P. DenBaars Michael S. Shur Michael G. Spencer George White This document was sponsored by the Office of Naval Research (ONR) and the National Science Foundation (NSF) under ONR Grant NOOO14-99-1-0529 and NSF Cooperative Agreement ENG-9707092, both awarded to the International Technology Research Institute at Loyola College in Maryland. The government has certain rights in this material. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the United States government, the authors' parent institutions, or Loyola College. ABSTRACTThis final report of ITRI's panel on high-temperature electronics in Europe consists of an executive summary, an introductory chapter, and six chapters by panel members on various aspects of wide bandgap electronics. The report also contains site reports for the various companies, labs, universities, and government offices that the panel visited in Europe. Comparisons are made between developments in Europe and the United States. Principal findings include: • European scientists and engineers see optoelectronics and high-power, high-frequency electronics as the major application opportunities for wide bandgap semiconductors.• The size of the GaN and SiC technology and device development effort in Europe is comparable with that in the United Statews.• Europe is ahead of the U.S. in in bulk GaN growth technology.• The United States is currently ahead in GaN-based device developments for light emitters, and high-power/high-frequency applications.• In silicon carbide technology, the U.S. is ahead in SiC bulk crystal and epitaxial production.• In R&D silicon carbide effort, European organization both academic and industrial have recently demonstrated outstanding results in both material growth (bulk and epi) and device development proving the leading position in the world; in the area ...

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Photoluminescence characteristics of AlGaN-GaN-AlGaN quantum wells

Cited by 116 publications

References 6 publications

The band alignment of Cu2O/ZnO and Cu2O/GaN heterostructures

The band alignment of Cu2O/ZnO and Cu2O/GaN heterostructures

Photoluminescence properties of AlN homoepilayers with different orientations

High-Temperature Electronics in Europe

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