M
M. J. Murphy
Researcher at Cornell University
Publications - 31
Citations - 5091
M. J. Murphy is an academic researcher from Cornell University. The author has contributed to research in topics: Heterojunction & Molecular beam epitaxy. The author has an hindex of 14, co-authored 31 publications receiving 4768 citations.
Papers
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Journal ArticleDOI
Two-dimensional electron gases induced by spontaneous and piezoelectric polarization charges in N- and Ga-face AlGaN/GaN heterostructures
Oliver Ambacher,Joseph A. Smart,James R. Shealy,Nils Weimann,K. Chu,M. J. Murphy,William J. Schaff,L.F. Eastman,Roman Dimitrov,L. Wittmer,Martin Stutzmann,W. Rieger,J. Hilsenbeck +12 more
TL;DR: In this article, the authors investigated the role of spontaneous and piezoelectric polarization on the carrier confinement at GaN/AlGaN and AlGaN/GaN interfaces.
Journal ArticleDOI
Two dimensional electron gases induced by spontaneous and piezoelectric polarization in undoped and doped AlGaN/GaN heterostructures
Oliver Ambacher,B. E. Foutz,Joseph A. Smart,James R. Shealy,Nils Weimann,K. Chu,M. J. Murphy,A. J. Sierakowski,William J. Schaff,L.F. Eastman,Roman Dimitrov,A. Mitchell,Martin Stutzmann +12 more
TL;DR: In this paper, a combination of high resolution x-ray diffraction, atomic force microscopy, Hall effect, and capacitance-voltage profiling measurements is used to calculate the polarization induced sheet charge bound at the AlGaN/GaN interfaces.
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Undoped AlGaN/GaN HEMTs for microwave power amplification
L.F. Eastman,V. Tilak,Joseph A. Smart,B.M. Green,E.M. Chumbes,Roman Dimitrov,Hyungtak Kim,Oliver Ambacher,Nils Weimann,T. Prunty,M. J. Murphy,William J. Schaff,James R. Shealy +12 more
TL;DR: In this paper, a two-dimensional electron gas (2DEG) is induced using the strong spontaneous and piezoelectric polarization inherent in the AlGaN/GaN structures, and three-dimensional nonlinear thermal simulations are made to determine the temperature rise from heat dissipation in various geometries.
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Two-dimensional electron gases in Ga-face and N-face AlGaN/GaN heterostructures grown by plasma-induced molecular beam epitaxy and metalorganic chemical vapor deposition on sapphire
Roman Dimitrov,M. J. Murphy,Joseph A. Smart,William J. Schaff,James R. Shealy,L.F. Eastman,Oliver Ambacher,Martin Stutzmann +7 more
TL;DR: In this paper, the growth of nominally undoped GaN/AlxGa1−xN/GaN (x < 0.4) high mobility heterostructures with N-face or Ga-face polarity on sapphire substrates by plasma-induced molecular beam epitaxy (PIMBE) and metalorganic chemical vapor deposition was studied.
Journal ArticleDOI
Role of Spontaneous and Piezoelectric Polarization Induced Effects in Group-III Nitride Based Heterostructures and Devices
Oliver Ambacher,Roman Dimitrov,Martin Stutzmann,B. E. Foutz,M. J. Murphy,Joseph A. Smart,James R. Shealy,Nils Weimann,K. Chu,M. Chumbes,B.M. Green,A. J. Sierakowski,William J. Schaff,L.F. Eastman +13 more
TL;DR: In this paper, the authors present theoretical and experimental results demonstrating how polarization induced electric fields and bound interface charges in group-III nitrides can lead to the formation of two-dimensional carrier gases suitable for the fabrication of high power microwave frequency transistors.