Browsing by Keywords "Gallium nitride"
Now showing items 1-20 of 72
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A 6-18 GHz GaN power amplifier MMIC with high gain and high output power density
(IEEE, 2019)A three-stage reactively-matched 6-18 GHz power amplifier MMIC design is presented. The design effort is focused on obtaining a low-loss output matching network for a high output power density. Active unit cells consist ... -
AlGaN/GaN HEMT-based fully monolithic X-band low noise amplifier
(Wiley, 2005-04)A fully monolithic AlGaN/GaN HEMT-based low noise amplifier is reported. The circuit demonstrated a noise figure of 3.5 dB, gain of -7.5 dB, input return loss of -7.5 dB, and output return loss of -15 dB at 8.5 GHz. The ... -
Analysis of defect related optical transitions in biased AlGaN/GaN heterostructures
(2010)The optical transitions in AlGaN/GaN heterostructures that are grown by metalorganic chemical vapor deposition (MOCVD) have been investigated in detail by using Hall and room temperature (RT) photoluminescence (PL) ... -
Buffer effects on the mosaic structure of the HR-GaN grown on 6H-SiC substrate by MOCVD
(Springer New York LLC, 2017)High-resistive GaN (>108 Ω cm) layers have been grown with different buffer structures on 6H-SiC substrate using metalorganic chemical vapor deposition reactor. Different combination of the GaN/AlN super lattice, low ... -
Characterization of AlInN/AlN/GaN heterostructures with different AlN buffer thickness
(Springer New York LLC, 2016)Two AlInN/AlN/GaN heterostructures with 280-nm- and 400-nm-thick AlN buffer grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD) have been investigated by x-ray diffraction (XRD), atomic force ... -
A charge inverter for III-nitride light-emitting diodes
(American Institute of Physics Inc., 2016)In this work, we propose a charge inverter that substantially increases the hole injection efficiency for InGaN/GaN light-emitting diodes (LEDs). The charge inverter consists of a metal/electrode, an insulator, and a ... -
Comparison of trimethylgallium and triethylgallium as "ga" source materials for the growth of ultrathin GaN films on Si (100) substrates via hollow-cathode plasma-assisted atomic layer deposition
(AVS Science and Technology Society, 2016-02)GaN films grown by hollow cathode plasma-assisted atomic layer deposition using trimethylgallium (TMG) and triethylgallium (TEG) as gallium precursors are compared. Optimized and saturated TMG/TEG pulse widths were used ... -
Controlled growth and characterization of epitaxially-laterally-overgrown InGaN/GaN quantum heterostructures
(IEEE, 2010)Crystal material quality is fundamentally important for optoelectronic devices including laser diodes and light emitting diodes. To this end epitaxial lateral overgrowth (ELO) has proven to be a powerful technique for ... -
Dark current reduction in ultraviolet metal-semiconductor-metal photodetectors based on wide band-gap semiconductors
(IEEE, 2009-10)Photodetectors on semi-insulating GaN templates were demonstrated. They exhibit lower dark current compared to photodetectors fabricated on regular GaN templates. Similar behavior observed in photodetectors fabricated on ... -
Demonstration of flexible thin film transistors with GaN channels
(American Institute of Physics Inc., 2016)We report on the thin film transistors (TFTs) with Gallium Nitride (GaN) channels directly fabricated on flexible substrates. GaN thin films are grown by hollow cathode plasma assisted atomic layer deposition (HCPA-ALD) ... -
Design of an X-band GaN based microstrip MMIC power amplifier
(Bilkent University, 2019-02)RF power amplifiers are crucial components of modern radar and communication systems. However, their design poses some challenges due to device limitations in high power and high frequency regime, as well as inherent ... -
Design of high power S-band GaN MMIC power amplifiers for WiMAX applications
(IEEE, 2011)This paper reports two different S band GaN MMIC PA designs for WiMAX applications. First PA has a 42.6 dBm output power with a 55%PAE @ 3.5 GHz and 16 dB small signal gain in the 3.2-3.8 GHz frequency range. When two of ... -
Design of multi-octave band GaN-HEMT power amplifier
(IEEE, 2012)This paper describes design, fabrication and measurement of 6 GHz - 18 GHz monolithic microwave integrated circuit (MMIC) amplifier. The amplifier is realized as coplanar waveguide (CPW) circuit using 0.3 μm-gate Gallium-Nitride ... -
Determination of energy-band offsets between GaN and AlN using excitonic luminescence transition in AlGaN alloys
(American Institute of PhysicsA I P Publishing LLC, 2006)We report the determination of the energy-band offsets between GaN and AlN using the linewidth (full width at half maximum) of an extremely sharp excitonic luminescence transition in Alx Ga1-x N alloy with x=0.18 at 10 K. ... -
Determination of the in-plane effective mass and quantum lifetime of 2D electrons in AlGaN/GaN based HEMTs
(2011)Magnetoresistance and Hall resistance measurements have been used to investigate the electronic transport properties of AlGaN/GaN based HEMTs. The Shubnikov-de Haas (SdH) oscillations from magnetoresistance, is obtained ... -
Effect of growth pressure on coalescence thickness and crystal quality of GaN deposited on 4H-SiC
(Elsevier, 2010-09-25)The influence of growth pressure on the coalescence thickness and the crystal quality of GaN deposited on 4HSiC by low pressure metalorganic vapor phase epitaxy was studied. It was shown that growth pressure has an impact ... -
Effect of substrate temperature and Ga source precursor on growth and material properties of GaN grown by hollow cathode plasma assisted atomic layer deposition
(IEEE, 2016)GaN thin films grown by hollow cathode plasma-assisted atomic layer deposition (HCPA-ALD) at two different substrate temperatures (250 and 450 °C) are compared. Effect of two different Ga source materials named as ... -
Effects of field plate on the maximum temperature and temperature distribution for gan HEMT devices
(American Society of Mechanical Engineers, 2016)Field plated GaN high electron mobility transistors (HEMTs) are widely preferred amongst other GaN HEMT devices because of their ability to regulate electric field at high power densities. When operated at high power ... -
Electric field dependence of radiative recombination lifetimes in polar InGaN/GaN quantum heterostructures
(IEEE, 2009)We report on external electric field dependence of recombination lifetimes in polar InGaN/GaN quantum heterostructures. In our study, we apply external electric fields one order of magnitude less than and in opposite ... -
Electron momentum and energy relaxation rates in GaN and AlN in the high-field transport regime
(The American Physical Society, 2003)Momentum and energy relaxation characteristics of electrons in the conduction band of GaN and AlN are investigated using two different theoretical approaches corresponding to two high electric-field regimes, one up to 1-2 ...
