Family of discretely sized silicon nanoparticles and method for producing the same

US6743406B2 · kind B2 · utility

Assignee

• The Board of Trustees of the University of Illinois · US

Inventors

• Munir H. Nayfeh · Urbana, US
• Gennadey Belomoin · Wheeling, US
• Satish Rao · Martinez, US
• Joel Therrien · Urbana, US
• Sahraoui Chaieb · Thuwal, SA

Key dates

• Filing date: Nov 21, 2001
• Grant date: Jun 1, 2004
• Expiry date: Dec 19, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S5/3031
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A family of discrete and uniformly sized silicon nanoparticles, including 1 (blue emitting), 1.67 (green emitting), 2.15 (yellow emitting), 2.9 (red emitting) and 3.7 nm (infrared emitting) nanoparticles, and a method that produces the family. The nanoparticles produced by the method of the invention are highly uniform in size. A very small percentage of significantly larger particles are produced, and such larger particles are easily filtered out. The method for producing the silicon nanoparticles of the invention utilizes a gradual advancing electrochemical etch of bulk silicon, e.g., a silicon wafer. The etch is conducted with use of an appropriate intermediate or low etch current density. An optimal current density for producing the family is ˜10 milli Ampere per square centimeter (10 mA/cm2). Higher current density favors 1 nm particles, and lower the larger particles. Blue (1 nm) particles, if any appreciable quantity exist depending on the selected current density, may be removed by, for example, shaking or ultrasound. After the etch, the pulverized wafer is immersed in dilute HF for a short time, while the particles are still connected to the wafer to weaken the linkag…