Electroluminescence from p-n Junction Leds Consisting of N-Doped and Cl-Doped ZnSe Layers
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ELECTROLUMINESCENCE FROM p-n JUNCTION LEDs CONSISTING OF N-DOPED AND Cl-DOPED ZnSe LAYERS K. Ohkawa, A. Ueno
and
T. Mitsuyu
Central Research Laboratories, Matsushita Electric Ind. Co., Ltd. Moriguchi, Osaka 570, Japan
ABSTRACT We have fabricated
ZnSe p-n junction
Pt/p-ZnSe/n-ZnSe/n-GaAs.
The dopant used
p-type good
ZnSe:N
was formed
rectification
by
properties.
nitrogen
We have
K was dominated by recombination acceptor
holes
emission
between
at
2.705 eV. donor
a new structure
for n-type ZnSe
radical
doping.
found that
The
and
the
was Cl,
LEDs
of and
exhibited
electroluminescence
emission between
Increasing
electrons
LEDs with
at
77
free electrons and
temperature,
recombination
free
holes
dominated
blue
bandedge
semiconductors
such
as
and
ZnS
emission region.
INTRODUCTION Wide
bandgap
promising materials diodes.
The
1I-VI
for blue
efficient
ZnSe
ZnSe
are
light-emitting diodes (LEDs) and blue LEDs
require
high-quality
p-n
laser
junction.
Generally, Li-doped ZnSe was used for the p-type layer of the p-n junction [1,2,3]. Unfortunately, the Li atoms in ZnSe are very diffusive at the
growth
temperature
high-quality succeeded Ix10
16
cm-
p-n
in growing 3
[4].
junction
p-type
by nitrogen
(5].
(MBE) growth
Therefore, by
ZnSe:N
Diffusion of N
MBE-grown
exhibits strong ZnSe
diffusion and optical
Li
difficult
doping.
with
hole
atoms in
ZnSe
100 nm [6].
to fabricate
Recently,
We
concentration at
our growth
of
the have
about
epitaxial conditions
We have also reported, for the
Cl-doped ZnSe which is low-resistivity n-type and
blue photoluminescence
scarcely diffuse
the
radical doping during molecular-beam
(325 *C, 4 hours) was less than first time,
it is very
using
(< 37
nm)
properties,
at N
(PL)
emission
our
growth
and Cl
are
[7].
The CI
conditions.
atoms
in
Considering
promising impurities
for
ZnSe p-n junctions. Elemental
Au have been widely
used as
an electrode
material
Mat. Res. Soc. Symp. Proc. Vol. 228. 021992 Materials Research Society
for p-
340
type ZnSe. However, Au electrode has large contact resistance between Au and p-type ZnSe and tends to exhibit rectifying characteristic [8], because avoid
the Fermi level of Au is higher than that of p-type
the problem
in ohmic
ZnSe/p-ZnSe/p-GaAs [2,9].
However,
barrier
exists
Considering
contact
to p-type
ZnSe,
ZnSe.
To
a structure of n-
has been adopted in a several works on ZnSe LEDs
a disadvantage in valence
with this device
band
at
the
design is that a
ZnSe/GaAs
large hole
heterointerface
[10].
these results, we have employed Pt as an electrode material
for p-type ZnSe,
because of its closer Fermi
level
to that of p-type
ZnSe
compared with Au. In
this paper,
we report
our
latest
development
of
p-n
junction
LEDs consisting of N-doped and Cl-doped ZnSe layers grown by MBE.
MBE GROWTH OF ZnSe p-n JUNCTION The
growth
ZnSe LED
structure we
of the structure
(100) orientation. n+ contacting
d
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