Research

CURRENT 

Interfacial Thermal Transport 

A unified fundamental understanding of interfacial thermal transport is missing due to the complicated nature of interfaces which involves complex factors such as interfacial bonding, interfacial mixing, surface chemistry, crystal orientation, roughness, contamination, and interfacial disorder. Our group has a MURI project studying interfacial thermal transport.


Ultra-Wide Bandgap Semiconductor Materials

We have a MURI project studying the thermal properties of ultra-wide bandgap semiconductors, such as Ga2O3, and devices. β-Ga2O3 has emerged as a promising candidate for electronic device applications because of its ultra-wide bandgap, high breakdown electric field, and large-area affordable substrates grown from the melt. However, its thermal conductivity is at least one order of magnitude lower than that of other wide bandgap semiconductors.


Thermal Analysis of GaN High Electron Mobility Transistors

AlGaN/GaN high electron mobility transistors are important for the development of next-generation RF communications, solar blind sensors, and power electronics.  However, the reliability of these devices is limited, in part, by the intense heating that occurs in the transistors during operation.


Flexible Electronics Packaging and Reliability

We are characterizing the interfacial adhesion in flexible electronics including solar cells and organic light emitting devices in order to improve mechanical reliability.  We are also investigating interface modification methods that improve the strength and durability of the interfaces.


Interface Materials for Power Electronic Packages

Conventional power electronic packages are vulnerable to interfacial cracking, delamination and failures due to the mismatch between the coefficients of thermal expansion of various material layers in them. This work investigates novel interface materials that enhance the durability of these packages retaining the thermal performance.


Thermal Energy Materials and Systems

The thermal energy materials and systems group is working to model and design efficient energy technologies which can be used to reduce energy consumption in buildings. Materials that can be used for thermal storage and better thermal management of electronics systems used in buildings are being developed.


ARCHIVE 

Carbon Nanomaterials

We explored developing growth and bonding methods to create high performance thermal interface materials using vertically aligned carbon nanotubes. Additional efforts went into methods to synthesize large area graphene films directl on dielectric substrates without a transfer process.


Thermal Management of High Power LEDs

In this work we used a variety of thermal metrology methods along with COMSOL FEA to quantify and model the temperature and stress distribution in UV LEDs. Packaging concerns and novel cooling methods were also investigated.


Thermal Modeling of Wide Bandgap Semiconductors

We were developing a multiscale thermal model to predict the hot spot temperature in GaN transistors.  In these devices, intense heating occurs at the gate edge on the drain side of the transistor. To address the transport on this scale, we were developing a coupled Monte Carlo-phonon simulator where phonon transport is handled using the Discrete Ordinates Method.


George Woodruff School of Mechanical Engineering