SEMICONDUCTOR LASERS WITH INDIUM CONTAINING CLADDING LAYERS
An embodiment of semiconductor laser comprising: (a) a GaN, AlGaN, InGaN, or AlN substrate; (b) an n-doped cladding layer situated over the substrate; (c) a p-doped cladding layer situated over the n-doped; (d) at least one active layer situated between the n-doped and the p-doped cladding layer, and at least one of said cladding layers comprises a superstructure structure of AlInGaN/GaN, AlInGaN/AlGaN, AlInGaN//InGaN or AlInGaN/AlN with the composition such that the total of lattice mismatch strain of the whole structure does not exceed 40 nm %.
1 . A semiconductor laser having a structure comprising:
(a) GaN, AlGaN, InGaN, or AlN substrate;
(b) an n-doped cladding layer situated over the substrate;
(c) a p-doped cladding layer situated over the n-doped cladding layer;
(d) at least one active layer situated between the n-doped cladding layer and the p-doped cladding layer, wherein
at least one of said cladding layers contains indium and comprises a superstructure of quaternary/binary, ternary/binary and/or quaternary/ternary sublayers.
2 . The semiconductor laser according to claim 1 wherein said at least one cladding layer that contains indium and comprises an superstructure of quaternary/binary, ternary/binary and/or quaternary/ternary sublayers has geometry and composition such that:
(i) the total lattice mismatch strain of the whole superstructure of said cladding layer relative to said substrate does not exceed 40 nm %; and/or
(ii) the total lattice mismatch strain of the semiconductor laser structure that is situated below said at least one cladding layer does not exceed 40 nm %; and or
(iii) the total lattice mismatch strain of the semiconductor laser structure that is situated below any higher cladding layer does not exceed 40 nm %’ and/or
(iii) the total lattice mismatch strain of the semiconductor laser structure does not exceed 40 nm %.
3 . The semiconductor laser according to claim 1 wherein said at least one cladding layer has a superlattice structure and comprises of least one of the following sublayer pairs:
(i) AlInGaN and GaN, (ii) AlInGaN and AlGaN, (iii) AlInGaN and InGaN, (iv) AlInGaN/AlN, (v) AlInN/GaN, or combinations thereof.
4 . The semiconductor laser according to claim 1 wherein the at least one of said cladding layers that contains indium and comprises a superstructure of quaternary/binary, ternary/binary and/or quaternary/ternary sublayer is an n-type cladding.
5 . The semiconductor laser according to claim 1 , wherein both p-type and n-type cladding layers contain indium.
6 . The semiconductor laser of claim 1 , wherein the at least one cladding layer comprises AlInGaN/GaN periodical structure; and another cladding layer is (i) an AlGaN/GaN superlattice; or (ii) GaN bulk material.
7 . The semiconductor laser of claim 1 , wherein the substrate comprises a semipolar plane of wurtzite crystal.
8 . The semiconductor laser of claim 7 , wherein the semipolar plane is situated at or is within degree 10 degrees orientation of the following planes: (11-22), (11-2-2), (20-21), (20-2-1), (30-31) or (30-3-1).
9 . The semiconductor laser of claim 1 configured to emit light at wavelength in the range 510-540 nm.
10 . A semiconductor laser comprising:
(i) GaN, AlGaN, InGaN, or AlN substrate;
(ii) an n-doped cladding layer situated over the substrate;
(iii) a p-doped cladding layer situated over the n-doped cladding layer;
(iv) at least one active layer situated between the n-doped and the p-doped cladding layer, and at least one of said cladding layers contains indium and comprises an alternating structure of least one of the following pairs: (i) AlInGaN and GaN, (ii) AlInGaN and AlGaN, (iii) AlInGaN and InGaN, (iv) AlInN and GaN, or (v) AlInGaN and AlN; and
the total lattice mismatch strain of the whole alternating structure of the cladding layer with the substrate does not exceed 40 nm %.
11 . The semiconductor laser of claim 10 , wherein (i) said substrate is GaN, and at least one cladding layer is a quaternary/binary superlattice-structure; or (ii) said substrate is GaN and the n-cladding layer is a superlattice-structure of AlGaInN/GaN.
12 . The semiconductor laser of claim 10 , wherein the p-doped cladding is AlGaN/GaN superlattice or GaN bulk material.
13 . A semiconductor laser comprising:
(i) GaN, AlGaN, InGaN, or AlN substrate;
(ii) an n-doped cladding layer situated over the substrate;
(iii) a p-doped cladding layer situated over the n-doped;
(iv) at least one active layer situated between the n-doped and the p-doped cladding layer,
and at least one of said cladding layers comprises a super structure of AlInGaN/GaN, AlInGaN/AlGaN, AlInGaN//InGaN, AlInGaN/AlN, or AlInN/GaN.
14 . The semiconductor laser of claim 13 wherein at least the n-doped cladding layer comprises a superlattice-structure of AlGaInN/GaN.
15 . The semiconductor laser of claim 1 , wherein said substrate is GaN with semipolar plane orientation.
16 . The semiconductor laser of claim 1 wherein the p-doped cladding layer comprises a superlattice-structure of AlGaN/GaN.
17 . The semiconductor laser according to claim 1 wherein the p-doped cladding layer has a thickness of at least 550 nm.
18 . The semiconductor laser according to claim 17 wherein the p-doped cladding layer has a thickness of at least 600 nm.
19 . The semiconductor laser according to claim 17 wherein the p-doped cladding layer has a thickness of at least 700 nm.