InGaN light emitting diodes (LED) structure with an embedded 1/4λ-stack nanoporous-GaN/undoped-GaN distributed Bragg reflectors (DBR) structure have been demonstrated. Si-heavily doped GaN epitaxial layers (n(+)-GaN) in the 12-period n(+)-GaN/u-GaN stack structure are transformed into low refractive index nanoporous GaN structure through the doping-selective electrochemical wet etching process....

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Sakari Sintonen Name of the doctoral dissertation Synchrotron radiation x-ray topography of crystallographic defects in GaN Publisher School of Electrical Engineering Unit Department of Microand Nanosciences Series Aalto University publication series DOCTORAL DISSERTATIONS 187/2014 Field of research Nanotechnology Manuscript s...

This work presents measured results demonstrating an uncooled infrared (IR) detector based on gallium nitride (GaN) micromechanical resonators. GaN-based photonic detectors are typically designed to operate in the ultraviolet (UV) regime as the absorption spectrum of wide-band gap GaN peaks at a wavelength of ~360 nm. In contrast, the transduction mechanism of the device presented in this work ...

We report the remarkably improved crystal quality of semi-insulating GaN grown by metalorganic chemical vapor deposition on an AlN buffer layer, which is deposited on sapphire substrate. The electrical and structural properties are characterized by dark current–voltage transmission line model and X-ray diffraction measurements. It is found that the crystal quality of the GaN epilayer is strongl...

Microwave GaN technology is now in production and poised to revolutionize many of today’s radar and communication systems. Simultaneously, mm-wave GaN processes are rapidly being matured to meet the growing needs of high power and efficiency, at higher frequencies. In this paper, we present an overview of GaN development, focusing on reliability and affordability for defense applications.

In this study, we have grown 380-nm ultraviolet light-emitting diodes (UV-LEDs) based on InGaN/AlInGaN multiple quantum well (MQW) structures on free-standing GaN (FS-GaN) substrate by atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD), and investigated the relationship between carrier localization degree and FS-GaN. The micro-Raman shift peak mapping image shows low standa...

KUANG, WEIWEI. TCAD Simulation and Modeling of AlGaN/GaN HFETs. (Under the direction of Dr. Robert J. Trew and Dr. Griff L. Bilbro). This work focused on the TCAD simulation and modeling of AlGaN/GaN HFETs. AlGaN/GaN HFETs have demonstrated excellent RF performance, which benefits from the high sheet charge density in these hetero-structures, the high carrier mobility and saturation velocity in...

Picosecond time-resolved photoluminescence ~PL! spectroscopy has been used to investigate the optical properties of GaN pyramids overgrown on hexagonal-patterned GaN~0001! epilayers on sapphire and silicon substrates with AlN buffer layers. We found that: ~i! the release of the biaxial compressive strain in GaN pyramids on GaN/AlN/sapphire substrate led to a 7 meV redshift of the spectral peak ...

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. AlGaN/GaN high electron mobility transistors (HEMTs) grown on Si substrates have attracted a great interest for pow...

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