Inorganic Bulk Multijunction Materials and Processes for Preparing the Same

• US 20110220874A1
• Filed: 08/10/2009
• Published: 09/15/2011
• Est. Priority Date: 08/08/2008
• Status: Abandoned Application

• Current Assignee: Cornell University
• Original Assignee: Cornell University
• Inventors: Hanrath, Tobias, Engstrom, James R.
• Application Number:
  US13/057,535
• Publication Number:
  US 20110220874A1
• Time in Patent Office: Days
• US Class Current: 257/22
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 19/007 Tellurides or selenides of metals C01B19/002 takes precedence
• CPC Class Codes: C01G 21/21 Sulfides
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: H01L 31/028 including, apart from doping material or other impurities, only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/0312 including, apart from doping materials or other impurities, only AIVBIV compounds, e.g. SiC
• CPC Class Codes: H01L 31/035281 Shape of the body
• CPC Class Codes: H01L 31/1864 Annealing
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A nanostructured composite material comprising semiconductor nanocrystals in a crystalline semiconductor matrix. Suitable nanocrystals include silicon, germanium, and silicon-germanium alloys, and lead salts such as PbS, PbSe, and PbTe. Suitable crystalline semiconductor matrix materials include Si and silicon-germanium alloys. A process for making the nanostructured composite materials. Devices comprising nanostructured composite materials.

Claims

1. ) A method of making a nanocrystal composite material comprising the steps of:

a) on a substrate, forming a layer of pre-composite material comprising an amorphous semiconductor matrix into which are incorporated semiconductor nanocrystals; and

b) subjecting the materials from a) to crystallizing conditions such that the amorphous semiconductor matrix material is crystallized and the semiconductor nanocrystals exhibit properties characteristic crystalline structure, to form a nanocrystal composite material.

2. ) The method of claim 1, wherein the forming a layer of pre-composite material step in a) is carried out by first depositing nanocrystals on the substrate and then forming the amorphous semiconductor matrix.

3. ) The method of claim 1, wherein the forming a layer of pre-composite material step in a) is carried out by first mixing semiconductor nanocrystals and precursors of an amorphous semiconductor matrix material and then depositing said mixture on the substrate.

4. ) The method of claim 2, wherein the forming the amorphous semiconductor matrix is carried out by deposition of precursor material followed by conversion of the precursor material to the amorphous semiconductor material.

5. ) The method of claim 2, wherein the forming of the amorphous semiconductor matrix is carried out by deposition of the amorphous semiconductor material.

6. ) The method of claim 1, wherein the semiconductor nanocrystals are from 2-30 nm in size.

7. ) The method of claim 1, wherein the semiconductor nanocrystals are selected from the group consisting of lead selenide, lead sulfide and germanium.

8. ) The method of claim 1, wherein the amorphous semiconductor matrix comprises material selected from the group consisting of silicon, germanium, and a silicon-germanium alloy (Si_1-xGe_x).

9. ) The method of claim 1, wherein the subjecting the materials from a) to crystallizing conditions is carried out by laser annealing.

10. ) The method of claim 1, wherein the semiconductor nanocrystals are present in the matrix at a volume fraction of from 0.2 to 0.74.

11. ) The method of claim 1, wherein the thickness of the nanocrystal composite material is from 20 to 400 nm.

12. ) A nanocrystal composite material comprising a plurality of semiconductor nanocrystals incorporated into a crystalline semiconductor matrix, wherein the majority of the nanocrystals have an ordered arrangement within the composite.

13. ) The composition of claim 12, wherein the semiconductor nanocrystals are selected from the group consisting of lead selenide, lead sulfide and germanium.

14. ) The composition of claim 12, wherein the semiconductor nanocrystals are from 2-30 nm in size.

15. ) The composition of claim 12, wherein the amorphous semiconductor matrix comprises material selected from the group consisting of silicon, germanium, and a silicon-germanium alloy (Si_1-xGe_x).

16. ) The composition of claim 12, wherein the thickness of the nanocrystal composite material is from 20 nm to 400 nm.

17. ) The composition of claim 14, wherein the crystalline semiconductor matrix is comprises silicon and the silicon grains are from 8 to 20 nm.

18. ) The composition of claim 12, wherein each of at least a majority of nanocrystals are electrically connected to adjacent nanocrystals.

19. ) A device for converting photons and/or thermal energy to electrical energy comprising:

at least two spaced electrodes; and

at least one layer comprising the nanocrystal composite material of claim 12 disposed between the two spaced electrodes.

20. ) The device of claim 19, wherein the nanocrystal composite material comprises lead selenide nanocrystals and silicon matrix.