Method of growing crystalline layers on amorphous substrates using two-dimensional and atomic layer seeds
This disclosure relates to methods of growing crystalline layers on amorphous substrates by way of an ultra-thin seed layer, methods for preparing the seed layer, and compositions comprising both. In an aspect of the invention, the crystalline layers can be thin films. In a preferred embodiment, these thin films can be free-standing.
1. A method of using seed layers to grow a thin film, comprising:
(a) growing or depositing a two-dimensional (2D) layer on a substrate; wherein the two-dimensional (2D) layer comprises one or more group-III chalcogenides (GIIIC);
(b) treating the two-dimensional (2D) layer to form one or more seed layers; wherein the one or more seed layers comprise a Group III nitride; and wherein the one or more seed layers are formed by annealing the two-dimensional (2D) layer in ammonia; and
(c) transforming the one or more seed layers into a thin film.
2. The method of claim 1 , wherein the substrate comprises silicon dioxide (SiO 2 ), silicon (Si), alumina (Al 2 O 3 ), aluminum nitride (AlN), beryllia (BeO), quartz, titanate, ferrite, and/or sapphire.
3. The method of claim 1 , wherein the two-dimensional (2D) layer is deposited on the substrate, and wherein the two-dimensional (2D) layer is obtained by exfoliation, wherein the exfoliation is liquid or mechanical exfoliation.
4. The method of claim 1 , wherein the Group III nitride is GaN or InN.
5. The method of claim 1 , wherein the one or more group-III chalcogenides (GIIIC) comprises gallium selenide (GaSe) and/or indium selenide (InSe).
6. The method of claim 1 , wherein the transforming step comprises conducting epitaxial growth, wherein the epitaxial growth comprises hydride vapor phase epitaxy (HVPE), chemical vapor deposition (MOCVD), plasma enhanced chemical vapor deposition (PECVD), molecular beam epitaxy (MBE), liquid phase exfoliation, and/or remote epitaxy.
7. The method of claim 1 , wherein the two-dimensional (2D) layer is grown on the substrate using powder vaporization (PV).
8. The method of claim 1 , wherein the one or more seed layers have a thickness of less than about 3 nm.
9. The method of claim 1 , wherein the one or more seed layers is a monolayer.
10. The method of claim 9 , wherein the thin film is a single-crystal film.
11. The method of claim 1 , wherein the one or more seed layers is a multilayer.
12. The method of claim 11 , wherein the thin film is a polycrystalline film.
13. The method of claim 1 , wherein the substrate is amorphous.
14. The method of claim 1 , wherein the thin film has a thickness of between about 50 nm to about 5 microns.
15. The method of claim 1 , wherein the method further comprises (d) mechanically exfoliating the thin film providing a free-standing thin film.