Quantum dots of group IV semiconductor materials

• US 7,402,832 B2
• Filed: 07/16/2004
• Issued: 07/22/2008
• Est. Priority Date: 08/02/2001
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: UltraDots, Inc. (Omnipv Incorporated)
• Inventors: Lee, Howard Wing Hoon
• Primary Examiner(s): Jackson, Jr., Jerome
• Application Number:
  US10/893,059
• Publication Number:
  US 20040262583A1
• Time in Patent Office: 1,467 Days
• Field of Search: 257/17, 257/22
• US Class Current: 257/17
• 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 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 2006/12097 Ridge, rib or the like
• CPC Class Codes: G02B 2006/12145 Switch
• CPC Class Codes: G02B 2006/12147 Coupler
• CPC Class Codes: G02B 2006/12159 Interferometer
• CPC Class Codes: G02B 2006/12195 Tapering
• CPC Class Codes: G02B 6/122 Basic optical elements, e.g. light-guiding paths
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02F 1/01791 Quantum boxes or quantum dots
• CPC Class Codes: G02F 1/217 Multimode interference type
• CPC Class Codes: G02F 1/3515 All-optical modulation, gating, switching, e.g. control of a light beam by another light beam G02F1/353, G02F1/37, G02F1/39 take precedence
• CPC Class Codes: G02F 1/3517 using an interferometer
• CPC Class Codes: G02F 1/3521 using a directional coupler
• CPC Class Codes: G02F 1/3556 Semiconductor materials, e.g. quantum wells
• CPC Class Codes: G02F 1/365 in an optical waveguide structure G02F1/377, G02F1/395 take precedence
• CPC Class Codes: G02F 2/006 All-optical wavelength conversion
• CPC Class Codes: G02F 2202/32 Photonic crystals
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials
• CPC Class Codes: H01L 29/127 Quantum box structures
• CPC Class Codes: H01L 29/16 : including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 29/1602 : Diamond
• CPC Class Codes: H01L 33/20 : with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/34 : containing only elements of Group IV of the Periodic Table
• CPC Class Codes: Y10S 977/814 : Group IV based elements and compounds, e.g. CxSiyGez, porous silicon

Abstract

The invention relates to a quantum dot. The quantum dot comprises a core including a semiconductor material Y selected from the group consisting of Si and Ge. The quantum dot also comprises a shell surrounding the core. The quantum dot is substantially defect free such that the quantum dot exhibits photoluminescence with a quantum efficiency that is greater than 10 percent.

Claims

1. A quantum dot comprising:

a) a core that is crystalline and including Ge; and

b) a shell that is inorganic and noncrystalline and including GeO_n with n between approximately 1.5 and 2, said shell surrounding said core and having a thickness greater than one monolayer of GeO_n and up to ten monolayers of GeO_n,

said quantum dot exhibits photoluminescence with a quantum efficiency that is at least 40 percent.

2. The quantum dot of claim 1, wherein said core has a diameter between approximately 1 nm and 20 nm.

3. The quantum dot of claim 1, wherein said core has a diameter between approximately 1 nm and 50 nm.

4. The quantum dot of claim 1, wherein said core has a diameter between approximately 1 nm and 10 nm.

5. The quantum dot of claim 1, wherein said core is substantially spherical with an aspect ratio between approximately 0.8 and 1.2.

6. The quantum dot of claim 1, wherein n is between approximately 1.8 and 2.

7. The quantum dot of claim 1, wherein said shell completely surrounds said core.

8. The quantum dot of claim 1, wherein said quantum efficiency is at least 50 percent.