CATALYST FREE SYNTHESIS OF VERTICALLY ALIGNED CNTs ON SiNW ARRAYS

• US 20140183450A1
• Filed: 03/30/2012
• Published: 07/03/2014
• Est. Priority Date: 03/31/2011
• Status: Active Grant

• Current Assignee: Council of Scientific & Industrial Research
• Original Assignee: Council of Scientific & Industrial Research
• Inventors: Shelke, Manjusha Vilas
• Granted Patent: US 9,305,777 B2
• Time in Patent Office: Days
• US Class Current: 257/22
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 2202/06 Multi-walled nanotubes
• CPC Class Codes: C01B 2202/36 Diameter
• CPC Class Codes: C01B 32/16 Preparation
• CPC Class Codes: C30B 25/00 Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
• CPC Class Codes: C30B 29/06 Silicon
• CPC Class Codes: C30B 29/60 characterised by shape
• CPC Class Codes: C30B 29/602 Nanotubes
• CPC Class Codes: H01L 21/02527 Carbon, e.g. diamond-like carbon
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02603 Nanowires
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 29/0676 oriented perpendicular or at an angle to a substrate
• CPC Class Codes: H10K 10/29 Diodes comprising organic-inorganic heterojunctions
• CPC Class Codes: H10K 85/221 Carbon nanotubes

Abstract

The present invention discloses novel one dimensional, direct nano-heterojunctions of vertically aligned silicon nanowires (SiNW)-carbon nano tube (CNT) arrays with ultra-low turn-on field useful in single electronic devices. The invention further discloses catalyst free chemical vapor deposition (CVD) route for synthesis of one dimensional, direct nano-heterojunctions of vertically aligned SiNW-CNT arrays.

Claims

1. A catalyst free chemical vapor deposition (CVD) process to obtain one dimensional, direct, nano-heterojunction arrays of SiNW-CNT comprising reacting sublimed aromatic hydrocarbons as carbon precursor with vertically aligned silicon nanowire (SiNW) to grow carbon nanotube (CNT) at the active tip of each vertically aligned silicon nano wire.

2. The catalyst free process according to claim 1, wherein the direct growth of carbon nanotube at the active tip of each vertically aligned SiNWs comprises;

(a) pyrolizing aromatic precursors at a temperature in the range of 150°

C.-350°

C. in a preheater zone followed by carrying sublimed carbon to the main reaction zone of CVD along with the flow of the carrier gas; and

(b) reacting incoming sublimed carbon with SiNW tips in the range of 900°

C. to 960°

C. in the main reaction zone to achieve complete vertical alignment of CNTs on SiNWs arrays.

3. The catalyst free process according to claim 1, wherein the direct nano-heterojunction arrays of vertically aligned SiNW-CNT are formed.

4. The catalyst free process according to claim 1, wherein the aromatic precursor is easily sublimable carbon precursor selected from naphthalene or anthracene.

5. The catalyst free process according to claim 1, wherein vertically aligned carbon nanotubes (CNT'"'"'s) comprises multi walled CNT(MWNT).

6. The catalyst free process according to claim 1, wherein the diameter of vertically aligned CNTs is in the range of 50-100 nm.

7. A catalyst free one dimensional, nano-heterojunction arrays with ultra-low turn-on field useful in single electronic devices comprising vertically aligned silicon nanowires and vertically aligned carbon nanotubes, wherein the vertically aligned carbon nanotubes are in direct contact with each vertically aligned silicon nanowires.

8. The catalyst free one dimensional, nano-heterojunction arrays according to claim 7, wherein the diameter of vertically aligned carbon nanotubes (CNTs) is in the range of 50-100 nm.

9. The catalyst free one dimensional, nano-heterojunction arrays according to claim 7, wherein vertically aligned carbon nanotubes (CNT'"'"'s) comprises multi walled CNT(MWNT).