Methods of exfoliating single crystal materials
Disclosed herein are methods for exfoliation of single crystals allowing for growth of high crystalline quality on the exfoliated surfaces for III-V photovoltaics. Also disclosed herein are methods for growing GaAs (111) on layered-2D Bi 2 Se 3 (0001) substrates in an MOCVD reactor.
1. A method for making a semiconductor device comprising exfoliating a Selenide-based 2D layered material whereby the exfoliation creates a surface of Selenide-based 2D layered material; and converting the surface of the Selenide-based 2D layered material to ZnSe.
2. The method of claim 1 wherein the ZnSe is lattice matched to the layer of Selenide-based 2D layered material.
3. The method of claim 1 wherein the ZnSe is lattice mismatched to the layer of Selenide-based 2D layered material.
4. The method of claim 1 wherein the Selenide-based 2D layered material comprises Bi 2 Se 3 .
5. The method of claim 1 wherein the surface of Selenide-based 2D layered material is converted to In 2 Se 3 before converting the surface to ZnSe.
6. The method of claim 1 further comprising epitaxial growth of GaAs on the layer of ZnSe.
7. The method of claim 1 further comprising lifting off the semiconductor device from the Selenide-based 2D layered material and using the resulting Selenide-based-2D layered material for making a semiconductor device.
8. The method of claim 1 wherein the resulting Selenide-based-2D layered material is a (0001) basal plane substantially free of surface steps.
9. The method of claim 8 wherein the ZnSe is lattice matched to the layer of Selenide-based 2D layered material.
10. The method of claim 8 wherein the ZnSe is lattice mismatched to the layer of Selenide-based 2D layered material.
11. The method of claim 8 wherein the Selenide-based 2D layered material comprises Bi 2 Se 3 .
12. The method of claim 8 wherein the surface of Selenide-based 2D layered material is converted to In 2 Se 3 before converting the surface to ZnSe.
13. The method of claim 8 further comprising epitaxial growth of GaAs on the layer of ZnSe.
14. The method of claim 8 further comprising lifting off the semiconductor device from the Selenide-based 2D layered material and using the resulting Selenide-based-2D layered material for making a semiconductor device.
15. A method for making patterned semiconductor layers, comprising exfoliating a Bi 2 Se 3 material whereby the exfoliation creates a surface that is a (0001) basal plane substantially free of surface steps; and laterally patterning the surface by masking portions of the surface and converting the non-masked portions of the surface to ZnSe; and epitaxial growth of GaAs on the patterned layer of ZnSe.
16. The method of claim 15 wherein the surface is converted to In 2 Se 3 before converting the non-masked portions of the surface to ZnSe.
17. The method of claim 15 wherein the Bi 2 Se 3 material that is a (0001) basal plane substantially free of surface steps is laterally patterned by masking portions of the surface material and converting the non-masked portions of the surface material to In 2 Se 3 or ZnSe.
18. The method of claim 17 wherein the surface of Bi 2 Se 3 is converted to In 2 Se 3 before laterally patterning the surface by masking portions of the surface and converting the non-masked portions of the surface to ZnSe.
19. A method for growing GaAs (111) on layered-2D Bi 2 Se 3 (0001) substrates in an MOCVD reactor wherein the first step is converting the surface layers of Bi 2 Se 3 (0001) to ZnSe by annealing in the presence of diethylzinc, and the second step is growing GaAs in the presence of triethylgallium and AsH 3 .
20. The method of claim 19 wherein the annealing of Bi 2 Se 3 (0001) in the presence of diethylzinc occurs at a temperature which decreases from 400° C. to 300° C. over about 20 min.