Wolfgang J. Choyke

 

Research Professor, Department of Physics and Astronomy

324 NPL

412-624–9251, 1479(fax)

choyke@pitt.edu

http://www.phyast.pitt.edu/people/fprofile.php?id=45

 

 

Wolfgang Choyke’s research interests focus on large bandgap semiconductors such as SiC, AlN and GaN. He has had a long interest in SiC which has emerged as the semiconductor of choice for high efficiency power devices and platforms for optoelectronic III-Nitride LED’s and lasers. SiC has been demonstrated to function extremely well at temperatures above 300C and radiation ambients well above anything that can be approached by Si. Research techniques which he has used over the years include: low temperature photoluminescence, low temperature optical absorption, derivative spectroscopy, excitation spectroscopy, Raman scattering and neutron scattering. The work of the Large Bandgap Semiconductor Group (with Devaty) touches nano-science and technology in many ways. We have had a large effort over the years to study stacking faults and nano-polytype inclusions. Over the past six years the Laboratory has focused on the development and understanding of photo-electrochemically produced nano-porous structures in the polytypes of SiC.  Ten morphologies have been identified and the nano-porous columnar structures (see figure) are currently being exploited as a basis for the reduction of defects in MOCVD grown GaN, biosensors, gas detectors and fuel cells.

 

 

 

 

 

 

Cross sectional SEM image of a semi-self organized nano-columnar porous SiC layer, produced by photo-electrochemical etching of single crystal 6H SiC in aqueous HF electrolyte. The ID of the pores is about 10nm and the length 250µm.