Semiconductor light-emitting devices

DETAILED DESCRIPTION It is an objective of the present invention to overcome the disadvantages of the prior art as set out above, by providing semiconductor light-emitting devices capable of emission wavelengths in the range extending from the blue to the ultra-violet regions of the spectrum.
In order to achieve this objective, a semiconductor light-emitting device according to the present invention has a structure that is based on an n-type semiconductor layer formed of a (ZnCd)(SSe) compound, and a p-type layer formed of a Cu(AlGa)(SSe).
sub.
2 or (ZnCd)Ga.
sub.
2 (SSe).
sub.
4 compound, epitaxially formed successively on a substrate, with each layer having an identical value of lattice constant to that of the substrate.
In the case of a semiconductor laser, an activation layer formed of a Cu(AlGa)(SSe).
sub.
2 type of compound is sandwiched between the p-type and n-type layers.
More specifically, according to a first aspect, a semiconductor light-emitting device according to the present invention, constituting a semiconductor laser, comprises a substrate and a combination of semiconductor layers disposed on the substrate in a double heterostructure laser configuration, the layers comprising: a p-type semiconductor cladding layer formed of Cu(Al.
sub.
a Ga.
sub.
1-a)(S.
sub.
b Se.
sub.
1-b).
sub.
2 where 0.
ltoreq.
a.
ltoreq.
1 and 0.
ltoreq.
b.
ltoreq.
1; an n-type semiconductor cladding layer formed of (Zn.
sub.
c Cd.
sub.
1-c)(S.
sub.
d Se.
sub.
1-d), where 0.
ltoreq.
c.
ltoreq.
1 and 0.
ltoreq.
d.
ltoreq.
1; and an activation layer disposed between the n-type cladding layer and p-type cladding layer and formed of Cu(Al.
sub.
a Ga.
sub.
1-a)(S.
sub.
b Se.
sub.
1-b).
sub.
2 ; each of the p-type cladding layer, n-type cladding layer and activation layer having an identical value of lattice constant to that of the substrate.
According to a second aspect, a semiconductor light-emitting device according to the present invention, constituting a light-emitting diode, comprises a substrate and a p-type semiconductor layer and n-type semiconductor layer formed as successive layers on the substrate, the p-type semiconductor layer being formed of Cu(Al