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High-Temperature Optical Characterization of GaN-Based Light-Emitting Diodes for Future Power Electronic Modules

Physica Status Solidi. A, Applications and Materials Science

Madhusoodhanan, Syam; Sabbar, Abbas; Atcitty, Stanley; Kaplar, Robert J.; Mantooth, Alan; Yu, Shui-Qing; Chen, Zhong

High-temperature optical analysis of three different InGaN/GaN multiple quantum well (MQW) light-emitting diode (LED) structures (peak wavelength λp = 448, 467, and 515 nm) is conducted for possible integration as an optocoupler emitter in high density power electronic modules. The commercially available LEDs, primarily used in the display (λp = 467 and 515 nm) and lighting (λp = 448 nm) applications, are studied and compared to evaluate if they can satisfy the light output requirements in the optocouplers at high temperatures. The temperature- and intensity-dependent electroluminescence (T-IDEL) measurement technique is used to study the internal quantum efficiency (IQE) of the LEDs. All three LEDs exhibit above 70% IQE at 500 K and stable operation at 800 K without flickering or failure. At 800 K, a promising IQE of above 40% is observed for blue for display (BD) (λp = 467 nm) and green for display (GD) (λp = 515 nm) samples. The blue for light (BL) (λp = 448 nm) sample shows 24% IQE at 800 K.

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TYPE Journal Article YEAR 2019
DOIOSTI

High Temperature and Power Dependent Photoluminescence Analysis on Commercial Lighting and Display LED Materials for Future Power Electronic Modules

Scientific Reports

Sabbar, Abbas; Madhusoodhanan, Syam; Al-Kabi, Sattar; Dong, Binzhong; Wang, Jiangbo; Atcitty, Stanley; Kaplar, Robert J.; Ding, Ding; Mantooth, Alan; Yu, Shui Q.; Chen, Zhong

Commercial light emitting diode (LED) materials - blue (i.e., InGaN/GaN multiple quantum wells (MQWs) for display and lighting), green (i.e., InGaN/GaN MQWs for display), and red (i.e., Al0.05Ga0.45In0.5P/Al0.4Ga0.1In0.5P for display) are evaluated in range of temperature (77–800) K for future applications in high density power electronic modules. The spontaneous emission quantum efficiency (QE) of blue, green, and red LED materials with different wavelengths was calculated using photoluminescence (PL) spectroscopy. The spontaneous emission QE was obtained based on a known model so-called the ABC model. This model has been recently used extensively to calculate the internal quantum efficiency and its droop in the III-nitride LED. At 800 K, the spontaneous emission quantum efficiencies are around 40% for blue for lighting and blue for display LED materials, and it is about 44.5% for green for display LED materials. The spontaneous emission QE is approximately 30% for red for display LED material at 800 K. The advance reported in this paper evidences the possibility of improving high temperature optocouplers with an operating temperature of 500 K and above.

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TYPE Journal Article YEAR 2019
DOIOSTIScopus

Saturation Velocity Measurement of Al0.7Ga0.3N-Channel High Electron Mobility Transistors

Journal of Electronic Materials

Klein, Brianna A.; Baca, Albert G.; Lepkowski, Stefan; Nordquist, Christopher D.; Wendt, Joel R.; Allerman, Andrew A.; Armstrong, Andrew A.; Douglas, Erica A.; Abate, Vincent M.; Kaplar, Robert J.

Gate length dependent (80 nm–5000 mm) radio frequency measurements to extract saturation velocity are reported for Al0.85Ga0.15N/Al0.7Ga0.3N high electron mobility transistors fabricated into radio frequency devices using electron beam lithography. Direct current characterization revealed the threshold voltage shifting positively with increasing gate length, with devices changing from depletion mode to enhancement mode when the gate length was greater than or equal to 450 nm. Transconductance varied from 10 mS/mm to 25 mS/mm, with the 450 nm device having the highest values. Maximum drain current density was 268 mA/mm at 10 V gate bias. Scattering-parameter characterization revealed a maximum unity gain bandwidth (fT) of 28 GHz, achieved by the 80 nm gate length device. A saturation velocity value of 3.8 × 106 cm/s, or 35% of the maximum saturation velocity reported for GaN, was extracted from the fT measurements.

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TYPE Journal Article YEAR 2019
DOIOSTIScopus

IRPS Increases its Coverage of SiC and GaN

Compound Semiconductor

Kaplar, Robert J.; Meneghini, Matteo; Lelis, Aivars

Over the past few years, interest has rocketed in the use of wide bandgap devices for energy-efficiency applications such as the electric grid, vehicle electrification, and more-electric aircraft. Deployed in these situations, devices must have a high reliability. In fact, this attribute is so crucial that it is a primary gatingfactor, determining the rate at which these wide bandgap devices are being inserted into these system applications.

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TYPE Journal Article YEAR 2019
OSTI
Results 101–125 of 346
Results 101–125 of 346
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