Wide bandgap semiconductor research

Research Fields

Our group has been active in the field of wide bandgap semiconductors, especially Gallium Nitride (GaN)since about 1994. The main research directions are

Other areas of research are

Various tools are employed for the characterization of electrical, optical, and structural properties of GaN materials and devices. We worked on various sponsored projects and produced several publications.


Gallium nitride (GaN) is a III-V semiconductor with a direct bandgap of about 3.4 eV. The material can be alloyed with InN and AlN, allowing for bandgap energies anywhere between 1.9 eV and 6.2 eV, and for the fabrication of heterostructures. Large interest in this materials system arises from the fact that efficient light emission at short wavelengths (green, blue, UV) can in principle be realized. Unfortunately there is no feasible bulk growth technique for nitride semiconductors. Therefore, the material is grown epitaxially on a substrate with poorly matched lattice constants and thermal expansion coefficients. The resulting low material quality, especially the high dislocation count, had initially discouraged any further work. However, persistent efforts to improve the growth procedure, noteworthy by Shuji Nakamura, have allowed the Japanese company Nichia to produce highly efficient green, blue, and UV light-emitting diodes (LED) as well as blue and ultraviolet laser diodes (LD). Today, Nitride-based devices are expected to generate large revenues in areas like DVD and laser printing (LD), microwave power applications (high electron mobility transistors, HEMT), and solid-state lighting including white-light generation (LED).

This page was made by Henning Feick 






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