November 30, 2015 Prof. Manfra receives Seeds of Success Award from Purdue University. This award recognizes research funding awards in excess of $1 million.
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October 26, 2015 Material grown by Manfra Group allows observation phase transition thought impossible. Read more.
October 15, 2015 Material grown by Manfra Group used to fabricate artificial graphene and featured as JVST Editors Pick. Read more.
October 5, 2015 Prof. Manfra named APS Fellow for advancing MBE growth of AlGaAs/GaAs and AlGaN/GaN heterostructures that enable fundamental understanding of 2D electron correlation effects and realization of novel devices.
The fractional quantum Hall effect (FQHE) occurs in a two-dimensional electron gas (2DEG) subjected to a perpendicular magnetic field at low temperature. It is now understood to arise from strong electron-electron interactions. In transport experiments the FHQE is characterized by Hall resistance quantized to rational fractional values of h/e2 and vanishingly small longitudinal resistance. Quasi-particle excitations in the FQHE are called anyons.
Nanostructures such quantum dots fabricated on modulation-doped AlGaAs/GaAs heterostructures are widely used in spin-based approaches to quantum computing. Charge noise in these devices, however, limits gate fidelity. A quiet electrostatic environment is therefore essential for further progress.
A major thrust in the Quantum Semiconductor Systems group is growth of extremely high quality GaAs/AlGaAs heterostructures. One metric of quality is 2D mobility, which can now exceed 30 x 106 cm2/Vs at low temperatures. At low temperature mobility is limited by imperfections in the grown sample. Imperfections include intentionally introduced charged impurities, unintentional background charged impurities and structural defects.
Our efforts are focused in 3 areas: improved MBE vacuum conditions, source material purity, and heterostructure design.
Our work in the III-Nitride material system is focused on exploiting its unique physical properties to produce novel light sources based on intersubband transitions. Due to the large conduction band offsets available in Al(In)GaN/GaN heterostructures, intersubband transitions can span the technologically important near-IR (~1.5microns) to far-IR (~100microns) spectral range.
March 9, 2015 John Watson successfully defended his thesis. Congratulations to John, good luck in Delft.
Bill and Dee O’Brian Chair Professor of Physics and Astronomy, Purdue University Professor of Electrical and Computer Engineering, Purdue University Professor of Materials Engineering, Purdue University PhD, Physics, Boston University, 1999 A.B. Cum Laude in Physics, Harvard University, 1992 Email: firstname.lastname@example.org Office: Room 84 (Physics) Room 1250 (Birck) Phone numbers: 765-494-3016 (Physics) 765-496-7703 (Birck) Professor […]
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