NCSU LEADS Research

Our Mission

The Laboratory for Electronics in Advanced Devices and Systems (LEADS) at NC State aims to understand and exploit the properties of novel materials and devices to break the performance barriers faced by today’s electronic circuits and systems. In partnership with both academic and industrial collaborators, we seek to make contributions to the entire cycle of electronic systems development: 1) performing fundamental studies of new materials, 2) integrating these materials into electronic devices and sensors to enhance performance, and 3) validating their potential through the deployment of devices and circuits in demanding applications relevant to the energy, telecommunications, medical, defense or space arenas.

Sponsors

These organizations have sponsored and/or continue to sponsor Prof. Pavlidis’s research.

Power Devices and Circuits

Power electronics form an integral part of our daily lives, though they are often overlooked because a successful power system should provide uninterrupted service, blending seamlessly into the background. Nonetheless, they form the core many of today’s critical technologies, ranging from cell phone and electric vehicle chargers; renewable energy capture, storage and distribution; high-performance communications and radar systems; as well as transportation in space and defense.

Through our affiliation with PowerAmerica, we are actively investigating the development of next-generation power devices using wide bandgap semiconductor materials, in particular gallium nitride (GaN) and silicon carbide (SiC). We design, fabricate and characterize power devices to maximize performance and assess reliability.

Example of Major Contribution: We demonstrated the first GaN-on-SiC HEMT-based power amplifier embedded within multilayer organic laminates, providing more than 7W of output power in a light-weight, low-cost form.

Please explore our publications for more information.

Flexible and Transparent Electronics

To enable the next generation of wearable electronics, we have investigate novel materials that enable high-performance devices without the need for high-temperature fabrication steps. This includes the use of indium gallium zinc oxide (IGZO) thin film transistors (TFTs) and 2D-material (e.g., graphene, MoS2) devices. To improve the stability of such devices in real-world applications, we have successfully demonstrated both circuit-level (e.g., pulsed-operation) and material-level (e.g., ALD passivation) techniques.

Example of Major Contribution: First to investigate and consequently demonstrate the use of low temperature ALD TiOx passivation for InGaZnO TFTs, in turn improving bias stress stability in both air and liquid. This led to our high-performance pH sensing (see below).

Please explore our publications for more information.

High-Frequency Devices, Circuits and Systems

In our mobile lives, wireless electronic systems play an integral role. Depending on the application, performance specifications such as frequency, bandwidth, power, noise and size will impact the choice of semiconductor technology, circuit topology and packaging.

We leverage the unique power handling capabilities of GaN technology to boost output power at high frequencies, and investigate novel techniques to package such devices while taking into account both thermal and RF parasitic effects. This permits us to implement both single-chip, as well as multi-chip, distributed circuit topologies. We have also demonstrated 3-D packages with heterogeneous semiconductor integration to provide best-in-class bandwidth. To provide low-cost and rapid development of high-frequency modules, we have also designed, fabricated and characterized 3-D printed modules up to 110 GHz.

Example of Major Contribution: Reported the widest bandwidth radio frequency receiver using heterogeneously integrated SiGe and GaAs chips in an encapsulated package.

Please explore our publications for more information.

Chemical and Biological Micro-Sensors

Chemical and biological sensors offer opportunities to monitor both personal health and that of the environment in which we live. We are engaged in the development of sensors with high sensitivity and stability, examining both gas-phase and liquid-phase analytes. Our primary focus is on charge-based sensors (e.g., FET), which can be tightly integrated with CMOS-based signal processing, though we have experience with alternative technologies, such as gravimetric MEMS devices. Our expertise goes beyond traditional silicon, however, as we seek to leverage new materials, such as amorphous and 2D semiconductors to realize high-performance devices in flexible/wearable form factors.

Example of Major Contribution: We demonstrated the first double-gated TFT pH sensor with super-Nernstian sensitivity using low temperature processes for flexible and portable sensors.

Please explore our publications for more information.