is a compound semiconductor and along with InN and
AlN forms a class of materials that have enabled white
and blue solid state lighting. Technology based on
thin films of GaN such as these are used in the white
(light emitting diode) flash lights and blue LEDs
(seen in cell phones for example).
Just like the Au nanoplatelet and the Ga2O3
nanowires seen in the images before, the GaN films
seen in the image to the left are also single crystals.
The hexagonal features, upper image on the left, reflect
the symmetry of arrangement of atoms within the material
which is also hexagonal. Actual devices require thin
films that are very smooth such as the one in the
figure on the left below. Thus, the film in the upper
image is actually a defective film. Part of Dr. Raghavan's
research is centered around trying to understand how
crystals grow and prevent such defects, with the ultimate
aim of being able to use them in actual devices.
These images are from his post-doctoral work at
The Pennsylvania State University with Dr.
Joan Redwing. He plans to continue his work on
crystal growth and growth of the Group III-A (Ga,
In, Al) nitrides at MRC.
For more information on Dr. Raghavan's research
visit his faculty
page and homepage.