III – V Materials and Devices

III-V materials and devices have very important applications in electronic and photonic systems. These applications drive our research programs which include:

• Multijunction solar cells for high conversion efficiency based on InGaAs/GaAsPN strained layer superlattices;
• Solid state lighting based on InGaN multiple quantum well structures emitting in the blue, green and red primary colors.;
• Three terminals LED structure emitting different colors for display devices;
• Spin-electronics and dilute magnetic semiconductors to take advantages of both electronic charge and spin for future optical and memory devices;
• Physics based compact modeling of III-V and silicon based FETs and HBTs for millimeter wave and minimum power circuit design;
• Exploration of novel devices in compound semiconductors and silicon based materials for ultra-low power operation;
• Use of oxides for novel device operation;
• Theoretical exploration of unexplained phenomena in emerging material systems.; Exploration of composite oxides with III-Nitride based materials for scaled metal oxide semiconductor devices;
• Nano-scaled heterogeneous source drains on intrinsic III-N materials;
• Chemistry of surface preparation and wet chemical etching in GaN;
• Use of III-Nitride properties for novel Gunn-effect terahertz device performance;
• Compact model extraction and development for GaN based devices

Optical Materials and Photonic Devices

Photonics is the science and technology of generating and controlling photons, particularly in the visible and near infra-red spectrum. Photonics as a science is closely related to quantum optics and optoelectronics with somewhat unclear boundaries. Quantum optics frequently implies fundamental research, while photonics often refers to more application-related research.

Many different fields use photonics regularly. Photonics is used by medical professionals to correct poor eyesight and to do laser surgery. The military uses it to detect mines. Construction companies do laser leveling and rangefinding by photonics. Even the entertainment industry finds uses for photonics in light shows and holographs.

Quantum Engineering

As feature sizes scale towards atomic dimensions in nanoelectronic devices quantum phenomena become dominamt. The quantum engineering groups explore quantum phenomena in nanoscale structures to discover and engineer effects that can be usefully employed for high performance computing and telecommunications applications, and for advanced concepts in sensor and biophysics devices.

This activity centers on semiconductor physics and modeling of electronic and optoelectronic devices in the nanoscale, low dimensional effects, quantum effects, quantum information processing/computing, spin electronics, molecular electronics, bionics/biological computing, nonlinear physics of solids, phonon processes in nanostructures, and collective electron and hole phenomena. We collaborate with experimental groups who investigate the properties of materials and devices of mutual interest.

Silicon Devices and Fabrication

Silicon technology continues to advance at an amazing rate. However, scaling of dimensions into the nano regeme presents a significant number of challenges for devices, materials, and integration technologies. Non-classical CMOS devices are needed to enhance performance at higher levels of integration.

New materials are needed for each new generation of devices; such materials include: high k dielectrics, metal gate electrodes, strain layers, molecules for charge storage, and carbon nanotubes. Low temperature-short time processes are needed to reduce interdiffusion. New methods to analyze, measure and control statistical fluctuations in small geometries. Research groups in this area also study the extension of the silicon technology base to address energy conversion, chemical- and bio-sensors, and nano-electro mechanical structure (NEMS) needs. Also of interest are manufacturing techonolgies to achieve large scale integration or reliable structures at affordable costs.