Rapid solid-state metathesis routes to nanostructured silicon-germainum
Methods for producing nanostructured silicon and silicon-germanium via solid state metathesis (SSM). The method of forming nanostructured silicon comprises the steps of combining a stoichiometric mixture of silicon tetraiodide (SiI 4 ) and an alkaline earth metal silicide into a homogeneous powder, and initating the reaction between the silicon tetraiodide (SiI 4 ) with the alkaline earth metal silicide. The method of forming nanostructured silicon-germanium comprises the steps of combining a stoichiometric mixture of silicon tetraiodide (SiI 4 ) and a germanium based precursor into a homogeneous powder, and initiating the reaction between the silicon tetraiodide (SiI 4 ) with the germanium based precursors.
1. A method of forming nanostructured silicon comprising the steps of:
(a) combining a stoichiometric mixture of silicon tetraiodide SiI 4 and an alkaline earth metal silicide into a homogeneous powder, and
(b) initiating the reaction between the silicon tetraiodide SiI 4 with the alkaline earth metal silicide.
2. The method of claim 1 , wherein the alkaline earth metal silicide is selected from the group consisting of: Mg 2 Si, CaSi 2 , and CaSi.
3. The method of claim 2 , wherein the initiating the reaction of the SiI 4 with the Mg 2 Si step comprises adding a predetermined amount of ethanol.
4. The method of claim 3 , wherein the initiating the reaction of the SiI 4 with the CaSi step comprises ball milling the SiI 4 and CaSi together.
5. The method of claim 2 , wherein the initiating the reaction of the SiI 4 with the CaSi step comprises resistively heating the powder using a nichrome wire.
6. The method of claim 1 , wherein the nanostructured silicon formed by the method comprises a morphology selected from the group consisting of nanoparticles, nanopowders, nanoclusters, nanocrystals, nanowires and mixtures thereof.
7. The method of claim 1 , wherein the method further comprises the step of washing a salt by-product from the nanostructured silicon with a solution selected from the group consisting of water, alcohol and mixtures thereof.
8. The method of claim 1 , wherein the method further comprises the step of etching a native oxygen layer from the nanostructured silicon by using a treatment comprising hydrofluoric acid.
9. A method of forming nanostructured silicon comprising the steps of:
(a) grinding a stoichiometric mixture of silicon tetraiodide SiI 4 and an alkaline earth metal silicide into a homogeneous powder, and
(b) reacting the silicon tetraiodide SiI 4 with the alkaline earth metal silicide.
10. The method of claim 9 wherein the alkaline earth metal silicide is selected from the group consisting of Mg 2 Si, CaSi 2 , and CaSi.
11. The method of claim 10 wherein the step of reacting the SiI 4 with the CaSi comprises resistively heating the powder using a nichrome wire.
12. The method of claim 10 , wherein the step of reacting the SiI 4 with the Mg 2 Si comprises adding a predetermined amount of ethanol.
13. The method of claim 10 , wherein the step of reacting the SiI 4 with the CaSi comprises ball milling the SiI 4 and CaSi together.
14. A method of forming nanostructured silicon comprising the step of
(a) ball milling a mixture of silicon tetraiodide SiI 4 and an alkaline earth metal silicide into a homogeneous powder, and
(b) reacting the silicon tetraiodide SiI 4 with the alkaline earth metal.
15. The method of claim 14 wherein the alkaline earth metal silicide is selected from the group consisting of Mg 2 Si, CaSi 2 , and CaSi.
16. The method of claim 15 wherein the step of reacting the SiI 4 with the Mg 2 Si comprises adding a predetermined amount of ethanol.
17. A method of forming nanostructured silicon-germanium comprising the steps of:
(a) combining a stoichiometric mixture of SiI 4 and a germanium based precursor into a homogeneous powder, and
(b) initiating the reaction between the SiI 4 and the germanium based precursor.
18. The method of claim 17 , wherein the germanium based precursor is selected from the group consisting of Mg 2 Ge and GeI 4 .
19. The method of claim 17 , wherein the combining step (a) comprises grinding the stoichiometric mixture of SiI 4 and an germanium based precursor into a homogeneous powder.
20. The method of claim 17 , wherein the grinding the stoichiometric mixture of SiI 4 and an germanium based precursor into a homogeneous powder is done in a glove box filled with argon and helium.
21. The method of claim 17 , wherein the combining step (a) comprises ball milling the mixture of silicon tetraiodide and the germanium based precursor into a homogeneous powder.
22. The method of claim 17 , wherein the initiating the reaction of the SiI 4 with the germanium based precursor comprises step comprises resistively heating the homogenous powder using a nichrome wire.
23. The method of claim 17 , wherein the initiating the reaction of the SiI 4 with the germanium based precursor comprises step comprises adding a predetermined amount of ethanol.
24. The method of claim 17 wherein the nanostructured silicon-germanium formed by the method comprises a morphology selected from the group consisting of nanoparticles, nanopowders, nanoclusters, nanocrystals, nanowires and mixtures thereof.
25. The method of claim 17 , wherein the method further comprises the step of washing a salt by-product from the nanostructured silicon-germanium with a solution selected from the group consisting of water, alcohol and mixtures thereof.
26. The method of claim 17 , wherein the method further comprises the step of etching a native oxygen layer from the nanostructured silicon by using a treatment comprising hydrofluoric acid.
27. A method of forming nanostructured silicon comprising the steps of:
(a) combining a stoichiometric mixture of SiI 4 and an alkaline earth metal silicide into a homogeneous powder,
(b) adding tin to the homogeneous powder, and
(c) initiating a reaction between the SiI 4 and the alkaline earth metal silicide.
28. A method of forming nanostructured silicon comprising the steps of:
(a) grinding a stoichiometric mixture of SiI 4 and an alkaline earth metal silicide into a homogeneous powder,
(b) adding tin to the homogeneous powder, and
(c) reacting the SiI 4 with the alkaline earth metal silicide.
29. A method of forming nanostructured silicon comprising the step of
(a) ball milling a mixture of SiI 4 and an alkaline earth metal silicide into a homogeneous powder,
(b) adding tin to the homogeneous powder, and
(c) reacting the SiI 4 with the alkaline earth metal silicide.