'Institute of Electrical and Electronics Engineers (IEEE)'
Doi
Abstract
High operating temperature i
nfrared
photo
detectors
with multi
-color function
that are
capable of monolithic
integration
are of increasing importance
in developing the next
generation
of
mid
-IR
imag
e sensors.
Applications of these sensors
include defense, medical diagnosis, environmental and
astronomical observations.
We
have
investigated a novel
InAsSb
-based nBnBn heterostructure that combines a state
-of-art
InAsSb nBn detector with
an
InAsSb/GaSb heterojuncti
on
detector
. At room temperature, r
educti
on
in the dark current
density of more than an order of magnitude
was
achieved
compared to
previously investigated
InAsSb/GaSb heterojunction
dete
ctors
.
Electrical
characterization
from
cryogenic
temperatures to roo
m temperature
confirmed that the nBnBn
device was diffusion limited
for temperature
s above 150K. O
ptical
measurements
demonstrated that the
nBnBn detector
was
sensitive in
both
the
SWIR and MWIR wavelength range at
room
temperature
. The specific
detectivity
(D*)
of the competed nBnBn
devices
was calculated to be
8.6
×
10
8
cm
·
Hz
1/2
W
-1
at 300K and
approximately 1.0
×
10
10
cm
·
Hz
1/2
W
-1
when cooled down to 200K
(with
0.3V reverse bias
and 1550nm illumination
). In addition,
all
photodetector layers were
grown monolithically on GaAs active
layers u
sing the interfacial misfit
array
growth
mode
. Our results
therefore pave the way
for the development of
new active pixel
designs for monolithically integrated mid
-IR imaging arrays