William Angerer - Department of Physics and Astronomy - University ...

Chapter 5
Properties of GaN
In recent years. the electronic, optical. and structural properties of the II 1-V nitrides
have been thoroughly investigated. Alloys with different atoms such as In, Ga. and .-\1
with N produce semiconductor materials with band gaps ranging from 1.9 to 6.2 e V.
The most significant motivation for these studies is the potential of II 1-V nitrides for
short-wavelength laser diode applications.
Commercial applications of short-wavelength laser diodes include optical storage.
laser printing, and display technologies. As an example of their superiority. we compare
digital video disks (DVD) systems with conventional long-wavelength diodes to
systems with short-wavelength diodes [62]. Short wavelength diodes are focused to a
smaller spot size than long-wavelength diodes. Present DVD-RO~l technology uses
diode lasers that emit between 635 and 650 nm and read 0.4 J-Lm pits separated by
0.74 J-Lm tracks. Storage for these disks is 4.7 Gbyte. By comparison, GaN" laser diode
based DVD systems (operating at wavelengths of 400 to 430 nm) are projected to
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