Journal ArticleDOI
Polarization-induced charge and electron mobility in algan/gan heterostructures grown by plasma-assisted molecular-beam epitaxy
I. P. Smorchkova,C. R. Elsass,J. P. Ibbetson,Ramakrishna Vetury,B. Heying,Paul T. Fini,E. Haus,Steven P. DenBaars,James S. Speck,Umesh K. Mishra +9 more
TLDR
In this article, the formation of the 2DEG in unintentionally doped AlxGa1−xN/GaN (x⩽0.31) heterostructures grown by rf plasma-assisted molecular-beam epitaxy is investigated.Abstract:
The formation of the two-dimensional electron gas (2DEG) in unintentionally doped AlxGa1−xN/GaN (x⩽0.31) heterostructures grown by rf plasma-assisted molecular-beam epitaxy is investigated. Low-temperature electrical-transport measurements revealed that the two-dimensional electron gas density strongly depends on both the thickness of the AlGaN layer and alloy composition. The experimental results agree very well with the theoretical estimates of the polarization-induced 2DEG concentrations. Low-temperature electron mobility was found to be much higher in the structures with lower electron sheet densities. Interface roughness scattering or alloy disorder scattering are proposed to be responsible for this trend. A maximum mobility of 51 700 cm2/V s (T=13 K) was obtained in the Al0.09Ga0.91N/GaN structure with a two-dimensional electron gas density of 2.23×1012 cm−2.read more
Citations
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Journal ArticleDOI
Band parameters for III–V compound semiconductors and their alloys
TL;DR: In this article, the authors present a comprehensive, up-to-date compilation of band parameters for the technologically important III-V zinc blende and wurtzite compound semiconductors.
Journal ArticleDOI
The impact of surface states on the DC and RF characteristics of AlGaN/GaN HFETs
TL;DR: In this article, the authors show that the cause of current collapse is a charging up of a second virtual gate, physically located in the gate drain access region, thus acting as a negatively charged virtual gate.
Journal ArticleDOI
Pyroelectric properties of Al(In)GaN/GaN hetero- and quantum well structures
Oliver Ambacher,Jacek A. Majewski,C. R. Miskys,A. Link,M. Hermann,Martin Eickhoff,Martin Stutzmann,Fabio Bernardini,Vincenzo Fiorentini,V. Tilak,B Schaff,L.F. Eastman +11 more
TL;DR: In this paper, it was shown that the macroscopic nonlinear pyroelectric polarization of wurtzite AlInN/GaN, InxGa1-xN and AlxIn1xN ternary compounds (large spontaneous polarization and piezoelectric coupling) dramatically affects the optical and electrical properties of multilayered Al(In)GaN/GAN hetero-, nanostructures and devices, due to the huge built-in electrostatic fields and bound interface charges caused by gradients in polarization at surfaces and heter
Journal ArticleDOI
A Review of GaN on SiC High Electron-Mobility Power Transistors and MMICs
TL;DR: Examples of broadband amplifiers, as well as several of the main areas of high-efficiency amplifier design-notably Class-D, Class-E, class-F, and Class-J approaches, Doherty PAs, envelope-tracking techniques, and Chireix outphasing are described.
Journal ArticleDOI
Structural characterization of nonpolar (112̄0) a-plane GaN thin films grown on (11̄02) r-plane sapphire
TL;DR: In this paper, structural characteristics of nonpolar (1120) a-plane GaN thin films grown on (1102) r-plane sapphire substrates via metalorganic chemical vapor deposition were described.
References
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Journal ArticleDOI
Spontaneous polarization and piezoelectric constants of III-V nitrides
TL;DR: In this paper, the spontaneous polarization, dynamical Born charges, and piezoelectric constants of the III-V nitrides AlN, GaN, and InN are studied ab initio using the Berry-phase approach to polarization in solids.
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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.
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Valence‐band discontinuities of wurtzite GaN, AlN, and InN heterojunctions measured by x‐ray photoemission spectroscopy
TL;DR: In this paper, the valence band discontinuities at various wurtzite GaN, AlN, and InN heterojunctions were measured by means of x-ray photoemission spectroscopy.
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Elastic constants of gallium nitride
TL;DR: The elastic constants of GaN have been determined using Brillouin scattering; in GPa they are: C11=390, C33=398, C44=105, C66=123, C12=145, and C13=106.
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Homoepitaxial growth of GaN under Ga-stable and N-stable conditions by plasma-assisted molecular beam epitaxy
TL;DR: In this article, the structure, morphology, and optical properties of homoepitaxial GaN layers grown by molecular beam epitaxy on metalorganic chemical vapor deposition (MOCVD)-grown GaN “template” layers were investigated as a function of the group III/group V flux ratio during growth.