{"id":10,"date":"2016-04-01T11:28:22","date_gmt":"2016-04-01T19:28:22","guid":{"rendered":"http:\/\/research.engineering.ucdavis.edu\/chowdhury\/?page_id=10"},"modified":"2016-08-11T22:31:19","modified_gmt":"2016-08-12T06:31:19","slug":"research-programs","status":"publish","type":"page","link":"https:\/\/research.engineering.ucdavis.edu\/chowdhury\/research-programs\/","title":{"rendered":"Research Programs"},"content":{"rendered":"

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\"Agencies\"<\/a><\/p>\n\n\n\n\n
Power Electronics<\/strong><\/p>\n

In collaboration with UCSB,\u00a0 this project aims to develop new vertical GaN transistors that will significantly enhance the performance and reduce the cost of high power electronics. Bulk GaN devices delivering 1.2kV switches form the core of our research.<\/p>\n<\/td>\n

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\"CAVET<\/a><\/td>\n<\/tr>\n
Fabrication and optimization of lateral AlGaN\/GaN MISHEMT with field-plates structure. High breakdown voltage up to 1kV.<\/td>\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\"AlGaN<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n\n
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High Frequency Electronics<\/strong><\/p>\n

It is critical that the Power Density and Power Added Efficiency (PAE) of RF RADAR amplifiers be maximized to reduce chip size and thermal cooling requirements. This enables new RADAR amplifier Classes such as switched mode amplifiers, reduces electrical and thermal system complexity and cost while simultaneously simplifying deployment.\u00a0Vertical GaN-based transistors uniquely harness the high breakdown field of GaN because the electric field distribution is uniform, easily designed and contained in the bulk of the device compared to peaked surface\/interface electric field distribution in lateral devices. Coupled with the reduced dispersion at high voltage they provide the desired high power density and PAE not possible with current technology.<\/p>\n<\/td>\n

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\"Power<\/a><\/td>\n<\/tr>\n

Terahertz\u00a0Electronics\u00a0<\/strong><\/p>\n

The performance gap preventing transistor operation at or near the terahertz regime makes the development of ultra-broadband wireless communication, advanced imaging and radar, electronic THz spectroscopy and THz digital computation, all critical components to enhance war-fighter capabilities, increasingly difficult.\u00a0To overcome this performance gap, we are looking into novel approaches tailoring E-k space to energize an electron beyond what is possible by scattering dominated transport.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n
High Temperature Electronics<\/strong><\/p>\n

Developing stable and low-resistivity ohmic contacts to GaN for high temperature InGaN solar cell operating above 450 \u00baC.\u00a0The high temperature InGaN solar cell will be attached to concentrated solar power to form a hybrid solar converter which could convert solar energy at higher efficiency and also provide dispatchable energy.<\/p>\n<\/td>\n

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \"Cross<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n
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Diamond Electronics\u00a0<\/strong><\/p>\n

Diamond is the ultimate material for power electronics. Diamond\u2019s wide band-gap, high predicted mobility and excellent thermal properties makes it an excellent candidate for future power devices. The progress with respect to diamond electronics has been impeded mainly due to the difficulty in growing homoepitaxial diamond (especially n-type) and the availability of single crystal bulk diamond substrates. The low work function of n-type diamond (0.9 eV) makes it difficult to form ohmic contacts.During the course of the project we have developed ohmic contacts to n-type diamond enabled by development of a novel growth scheme in Dr. Robert Nemanich\u2019s group at ASU where Phosphorus doped n-type films with high doping can be grown epitaxially. The final goal of the project is to develop a 1.2 kV diamond based Bipolar Junction Transistor and a 5kV diode.<\/p>\n

Moreover, Surface conduction by a 2D-hole gas formed through hydrogen termination, a property unique to diamond, can be utilized to make lateral FETs that can operate as high as 120 GHz. Our research also involves pushing beyond these limits of frequency and power in lateral diamond FETs by improving different parameters that operate the lateral FETs.<\/p>\n

Selected Publication :<\/p>\n