Studies on InAsN bulk films and MBE growth of GaSb

The growth and characterization of
InAsN alloys with various nitrogen contents
on InP substrates by using plasma-assisted gas
source molecular beam epitaxy are reported.
DXRD, Hall, and FTIR measurements were
used to study the structural, electrical and
optical properties of these alloy film. When
N composition increases, InAsN film has
broader FWHM in DXRD spectrum and
higher residual carrier concentration. Possible
origin of the high carrier concentration in
InAsN sample is currently under investigation.
Absorption spectra of these films show that
the fundamental absorption energy of InAsN is
higher than that of InAs. This is due to
Burstein-Moss effect caused by the residual
carriers. To educe the ‘real’ band gap energy
of our IdnAsN samples, the energy shift due to
band-filling effect and the band gap
renormalization effect are calculated by using
a self-consistent approach based on the
band-anticrossing model. After the correction,
the ‘real’ band gap energy of InAsN samples
decreases as N increases, follows the bowing
effect.
We have also studied the growth of
GaSb on GaAs or GaSb substrates by solid
source molecular beam epitaxy. By using Sb
monomer produced by the Sb cracker cell as
the group V source, we have studied the effect
of V/III ratio and growth temperature to the
GaSb film quality. After optimizing growth
parameters like growth temperature and
Sb/Ga ratio, we can observe bound exciton
transition at 0.802eV and free exciton
transition at 0.810eV in low temperature(10K)
PL. This shows the good quality of the grown
GaSb film.