GaN & Wide-Bandgap Semiconductor Devices
Handel made pioneering contributions to understanding and optimizing noise, reliability, and performance in GaN-based heterostructure devices, particularly High Electron Mobility Field Effect Transistors (HEMTs/HFETs) for RF power amplifiers and high-frequency electronics. Through extensive collaborations with Hadis Morkoç and others from 2000 onward, Handel developed comprehensive theoretical frameworks for piezoelectric quantum 1/f noise in GaN/AlGaN heterostructures, showing how strain-induced polarization fields and crystal structure uniquely affect noise generation in nitride semiconductors.
His research fundamentally changed GaN device development by establishing that 1/f noise measurements serve as diagnostic windows into device stability and reliability, enabling non-destructive prediction of degradation and failure modes. This work provided the theoretical foundation for optimizing device geometry, material quality, and operating conditions to minimize phase noise in oscillators and maximize sensitivity in detectors, directly enabling the revolution in GaN-based power amplifiers, radar systems, and 5G wireless infrastructure.
Key Publications
#195
Quantum 1/f Noise in GaN Materials and Devices
WOCSDICE 2000 Conference Proceedings
#199
Quantum 1/f Noise in GaN/Al0.15Ga0.85N Doped Channel HFETs
8th van der Ziel Symposium, St. Louis (2000)
#209
Quantum 1/f Noise in GaN/AlGaN HFET's and Phase Noise in RTDs
WOCSDICE 2001, Sardinia
#214
Quantum 1/f Noise in Epitaxial Lateral Overgrown GaN: Piezoelectric Effect
Semiconductor Science and Technology 17, 617-620 (2002)
This paper by Sia, Chua, Hartnagel, and Handel examines quantum 1/f noise in epitaxial lateral overgrown (ELO) GaN with particular focus on the piezoelectric effect. The research investigates how piezoelectric coupling in GaN crystal structures contributes to low-frequency 1/f noise, with implications for the design and optimization of GaN-based devices such as high-electron-mobility transistors (HEMTs) and optoelectronic components where noise performance is critical.
#223
Quantum 1/f Noise in GaN/AlGaN HEFTs and Other Nanodevices
ICNF'03, Prague
This paper by Handel, Lin, Mishra, and Shen examines quantum 1/f noise in GaN/AlGaN High Electron Mobility Field Effect Transistors (HEFTs) and other nanodevices. The research analyzes the fundamental quantum mechanical sources of low-frequency 1/f noise in gallium nitride based heterostructures, which are critical for high-power, high-frequency electronics and RF applications, providing theoretical predictions and guidance for optimizing device design to minimize noise and improve performance in communications, radar, and power electronics systems.
#226
1/f Noise Measurement and Theory in GaN HEFTs, Other Devices and Systems
WOCSDICE 2003
This paper by Handel and Lin presents 1/f noise measurement and theory in GaN HEFTs (High Electron Mobility Field Effect Transistors) and extends to other devices and systems. The research combines experimental noise measurements with quantum theoretical predictions for gallium nitride based transistors, providing a comprehensive analysis of low-frequency noise sources and their impact on device performance, reliability, and system-level applications in wireless communications, power amplifiers, and high-frequency circuits.
#232
GaN HEMT Geometry and Piezoelectric Quantum 1/f Noise
WOCSDICE 2004
This WOCSDICE 2004 paper by Handel, Hartnagel, Sia, Mishra, and York examines GaN HEMT geometry and piezoelectric quantum 1/f noise. The research investigates how the physical geometry and structural design of gallium nitride High Electron Mobility Transistors affect piezoelectric-induced quantum 1/f noise, providing insights for optimizing device layout, channel dimensions, and heterostructure configurations to minimize noise while maintaining high-frequency performance in GaN-based RF and power electronics applications.
#238
1/f Noise in GaN/AlGaN HFET Based Oscillators
Cardiff University Press (2005)
This paper by Handel, Tournier, Hartnagel, Mishra, and York investigates 1/f noise in GaN/AlGaN HFET based oscillators. The research analyzes how low-frequency 1/f noise in gallium nitride transistors upconverts to phase noise in oscillator circuits, affecting the spectral purity and stability of RF signal sources built with GaN technology, providing design guidelines for minimizing phase noise in GaN-based voltage-controlled oscillators, frequency synthesizers, and local oscillators for radar and communications systems.
#239
Quantum 1/f Phase Noise in GaN/AlGaN HFET Based Oscillators
Cardiff University Press (2005)
This paper by Handel, Tournier, Hartnagel, Mishra, and York examines quantum 1/f phase noise in GaN/AlGaN HFET based oscillators. The work provides a quantum mechanical analysis of phase noise generation in gallium nitride transistor-based oscillators, explaining how fundamental quantum 1/f noise processes in the semiconductor heterostructure translate into close-in phase noise sidebands around the carrier frequency, with implications for synthesizer jitter, receiver sensitivity, and system performance in wireless infrastructure and military electronics.
#254
Quantum 1/f Noise in GaN FETs, MODFETs, and their Oscillators' Phase Noise (Invited)
SPIE Conf. 6473 (2007)
This invited SPIE paper by Handel, Hall, and Morkoç examines quantum 1/f noise in GaN FETs, MODFETs, and their oscillators' phase noise. The research provides comprehensive analysis of low-frequency noise in gallium nitride field-effect transistors and modulation-doped FETs, and demonstrates how this baseband noise upconverts to phase noise sidebands in oscillator applications, offering theoretical predictions and design strategies for minimizing phase noise in GaN-based RF sources for radar, satellite communications, and high-power microwave systems.
#255
1/f Noise in the Dark Current of GaN QWIPs
SPIE Conf. 6473 (2007)
This SPIE paper by Hall and Handel investigates 1/f noise in the dark current of GaN Quantum Well Infrared Photodetectors (QWIPs). The research analyzes low-frequency fluctuations in the leakage current of gallium nitride based infrared detectors, which limits detection sensitivity particularly at low frequencies relevant to imaging and tracking applications, showing how quantum 1/f noise contributions in the dark current establish fundamental noise floors for GaN QWIP focal plane arrays in thermal imaging and night vision systems.
#262
Use of Quantum 1/f Noise Formulas in the Reliability Characterization of Nitride-Based Heterostructures
SPIE Vol. 6894 (2008)
This paper by Handel, Morkoç, and Truong discusses use of quantum 1/f noise formulas in the reliability characterization of nitride-based heterostructures, published in SPIE Proceedings on Gallium Nitride Materials and Devices. The research demonstrates how analyzing 1/f noise measurements using quantum noise theory provides insights into defect dynamics, degradation mechanisms, and reliability physics in GaN/AlGaN heterostructure devices, offering non-destructive testing methods for assessing long-term stability and predicting failure modes in high-power electronics and RF amplifiers.
#263
Piezoelectric Quantum 1/f Noise in Nitride-Based Heterostructures (Invited)
SPIE Vol. 6894 (2008)
This invited SPIE paper by Handel, Morkoç, Sia, and Truong examines piezoelectric quantum 1/f noise in nitride-based heterostructures. The research provides detailed analysis of how piezoelectric coupling in gallium nitride and aluminum gallium nitride heterostructures contributes to quantum 1/f noise through strain-induced polarization fields and phonon interactions, with implications for understanding noise mechanisms in GaN HEMTs, optimizing heterostructure design to minimize noise, and improving performance of GaN-based power amplifiers and RF devices.
#264
1/f Noise in Nitride-Based Spintronic Devices
SPIE Vol. 6894 (2008)
This SPIE paper by Handel and Truong investigates 1/f noise in nitride-based spintronic devices. The research examines low-frequency noise in gallium nitride based spin-electronic devices that exploit both charge and spin degrees of freedom for magnetic sensing, data storage, and logic applications, analyzing how quantum 1/f noise affects spin injection efficiency, magnetoresistance fluctuations, and read/write performance in GaN-based spin valves, magnetic tunnel junctions, and spin field-effect transistors relevant to next-generation non-volatile memory and quantum information processing.
#272
Piezoelectric Quantum 1/f Noise in AlGaN HFETs and Reliability
SPIE Vol. 7216 (2009)
This SPIE paper by Handel and Morkoç examines piezoelectric quantum 1/f noise in AlGaN HFETs and reliability. The research investigates how piezoelectric-induced quantum 1/f noise correlates with reliability and degradation in aluminum gallium nitride high electron mobility transistors, showing that low-frequency noise measurements can serve as early indicators of defect formation, trap generation, and impending failure, providing non-destructive diagnostic tools for assessing device quality and predicting long-term reliability in GaN-based power amplifiers and switches.
#279
1/f Noise: A Window to HFET Stability
SPIE-PW'10
This SPIE-PW paper by Handel, Sherif, Kayis, Leach, Zhu, and Morkoç demonstrates that 1/f noise serves as a window to HFET stability. The research shows that low-frequency noise measurements provide diagnostic information about defect states, trap dynamics, and degradation processes in heterostructure field-effect transistors, establishing correlations between noise parameters and device reliability, enabling predictive testing and quality control for ensuring long-term stable operation of GaN and other compound semiconductor transistors.
#291
Low-frequency Noise Measurements of AlGaN/GaN MOS HFETs with HfAlO Gate Dielectric
IEEE Electron Device Letters Vol. 31, 1041-1043 (2010)
This IEEE Electron Device Letters paper by Kayis, Leach, Zhu, Wu, Li, Özgür, Morkoç, Yang, Misra, and Handel examines low-frequency noise measurements of AlGaN/GaN MOS HFETs with HfAlO gate dielectric. The research investigates how hafnium aluminum oxide high-k dielectric affects 1/f noise in metal-oxide-semiconductor heterostructure field-effect transistors, comparing noise performance with conventional Schottky gate devices and analyzing the role of interface traps and dielectric quality in determining noise characteristics relevant to low-noise amplifier applications.