Extended short-wave infrared strain-layered superlattice on indium arsenide substrate and associated methods
Materials and methods may be provided for short-wave infrared (SWIR) superlattice materials. The superlattice material includes a first sub-layer comprising InAs, and a second sub-layer adjacent to the first sub-layer including AlSb, AlAsSb, or InAlAsSb.
1. An infrared detector comprising:
an InAs substrate; and
a strain-layered superlattice including:
a first sub-layer comprising InAs on the InAs substrate;
a second sub-layer directly on the first sub-layer comprising InAlAsSb;
a third sub-layer comprising InAs on the second sub-layer; and
a fourth sub-layer comprising InAlAsSb directly on the third sub-layer.
2. The infrared detector of claim 1 , wherein a thickness of the first sub-layer ranges from about 10 to 50 angstroms and wherein a thickness of the second sub-layer ranges from about 10 to 30 angstroms.
3. The infrared detector of claim 1 , wherein the InAlAsSb is present as In 0.2 Al 0.8 As 0.30 Sb 0.7 , In 0.5 Al 0.5 As 0.5 Sb 0.5 , or In 0.5 Al 0.5 As 0.57 Sb 0.43 .
4. The infrared detector of claim 1 , wherein the infrared detector detects infrared wavelengths of about 1 μm to 3 μm.
5. A structure comprising:
an InAs substrate;
a strain-layered superlattice including:
a first sub-layer comprising InAs on the InAs substrate;
a second sub-layer directly on the first sub-layer comprising InAlAsSb; and
a plurality of periods on the second sub-layer, each of the plurality of periods including:
a third sub-layer comprising InAs; and
a fourth sub-layer adjacent to the third sub-layer comprising InAlAsSb.
6. The structure of claim 5 , wherein a thickness of the first sub-layer and the third sub-layer in each of the plurality of periods ranges from about 10 to 50 angstroms, and wherein a thickness of the second sub-layer and the fourth sub-layer in each of the plurality of periods ranges from about 10 to 30 angstroms.
7. The structure of claim 5 , wherein the InAlAsSb is present as In 0.2 Al 0.8 As 0.30 Sb 0.7 , In 0.5 Al 0.5 As 0.5 Sb 0.5 , or In 0.5 Al 0.5 As 0.57 Sb 0.43 .
8. The structure of claim 5 , which detects infrared wavelengths of about 1 μm to 3 μm.
9. The structure of claim 5 , wherein the structure is doped n-type.
10. An infrared detector comprising the structure of claim 5 in an absorber region of the infrared detector.
11. An infrared camera, comprising a focal plane array comprising the infrared detector of claim 10 .
12. A PIN (p-doped semiconductor layer, intrinsic detector layer, and n-doped semiconductor layer) detector, PBN (p-doped semiconductor layer, barrier layer, and n-doped semiconductor layer), detector, or NBN (n-doped semiconductor layer, barrier layer, and n-doped semiconductor layer) detector comprising the structure of claim 5 .
13. A method comprising:
providing an InAs substrate;
forming a strain-layered superlattice by:
depositing a first sub-layer of InAs on the InAs substrate;
depositing a second sub-layer of InAlAsSb directly on the first sub-layer;
depositing a third sub-layer of InAs on the second sub-layer; and
depositing a fourth sub-layer of InAlAsSb directly on the third sub-layer.
14. The method of claim 13 , wherein:
depositing the second sub-layer comprises epitaxially growing the InAlAsSb on the first sub-layer; and
forming the strain-layered superlattice further comprises forming a plurality of periods on the fourth sub-layer, each of the plurality of periods including:
a fifth sub-layer comprising InAs; and
a sixth sub-layer directly on the fifth sub-layer comprising InAlAsSb.
15. The method of claim 14 , wherein the InAlAsSb is epitaxially grown using molecular beam epitaxy (MBE) or metallo organic chemical vapor deposition (MOCVD).
16. The method of claim 13 , wherein a thickness of the deposited second sub-layer is about 10 to 30 angstroms and wherein a thickness of the deposited first sub-layer is about 10 to 50 angstroms.
17. The method of claim 13 , further comprising determining a cut-off wavelength for the strain-layered superlattice, and adjusting a thickness of a sub-layer of the strain-layered superlattice based on the cut-off wavelength.
18. A method of forming an infrared detector assembly comprising:
forming the strain-layered superlattice according to the method of claim 13 ; and
forming at least one infrared detector element over the strain-layered superlattice.
19. The method of claim 18 , wherein the infrared detector assembly comprises a PBN (p-doped semiconductor layer, barrier layer, and n-doped semiconductor layer) device.
20. The method of claim 18 , wherein the strain-layered superlattice has a thickness of about 1 μm, and wherein the strain-layered superlattice detects infrared wavelengths of about 1 to 3 μm.