(10) Patent No.: US 7,691,731 B / A1 * 5/2005 Sato et al / / A1 * 6/2006 Fujii eta! /499 (57) ABSTRACT

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1 US B2 c12) United States Patent Bet et al. (10) Patent No.: US 7,691,731 B2 (45) Date of Patent: Apr. 6, 2010 (54) DEPOSITION OF CRYSTALLINE LAYERS ON POLYMER SUBSTRATES USING NANOPARTICLES AND LASER NANOFORMING (75) Inventors: Sachin M. Bet, Orlando, FL (US); Aravinda Kar, Oviedo, FL (US) (73) Assignee: University of Central Florida Research Foundation, Inc., Orlando, FL (US) ( *) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 143 days. (21) Appl. No.: 11/686,572 (22) Filed: Mar. 15, 2007 (65) (60) (51) (52) (58) (56) US 2007/ Al Prior Publication Data Sep.20,2007 Related U.S. Application Data Provisional application No. 60/782,667, filed on Mar. 15, Int. Cl. HOJL HOJL U.S. Cl.... ( ) ( ) 438/479; 438/478; 257/E Field of Classification Search /479; 257/E See application file for complete search history. 2003/ A1 * 2004/ A1 2004/ A1 * 2005/ A1 * References Cited U.S. PATENT DOCUMENTS 6/2003 Cross et al /107 9/2004 Yamazaki eta!. 12/2004 Nagasawa eta! /772 3/2005 Lalli et al / / A1 * 5/2005 Sato et al / / A1 * 6/2006 Fujii eta! /499 OTHER PUBLICATIONS Ichitsubo, T; Koujina, M; Kawashima, M.; Hirao, M. Fabrication of isolated FePd nanoparticles by sputtering and heat treatment May, 2003 Japan Society of Applied Physics vol. 42 pp * (Continued) Primary Examiner-Alexander G Ghyka Assistant Examiner-Abdulfattah Mustapha (74) Attorney, Agent, or Firm-letter & Associates, P.A. (57) ABSTRACT A method of forming crystalline semiconducting layers on low melting or low softening point substrates includes the steps of providing an aqueous solution medium including a plurality of semiconductor nanoparticles dispersed therein having a median size less than 10 nm, and applying the solution medium to at least one region of a substrate to be coated. The substrate has a melting or softening point of <200 C. The solution medium is evaporated and the at least one region is laser irradiated for fusing the nanoparticles followed by annealing to obtain a continuous film having a recrystallized microstructure. An article includes a polycrystalline semiconducting layer including a plurality of crystallites predominately in the size range of 2 to 50 f.1lll, and a substrate having a melting or softening point of <200 C. supporting the semiconducting layer. An average grain size of the crystallites is less at an interface proximate to the semiconducting layer as compared to an average grain size further away from the interface. 9 Claims, 8 Drawing Sheets Laser heating Aqueous dispersion of silicon nanoparticles Stage I 160 / Coalescence and film formation UO IN Neck formation and sintering (a) 195 /I\ c(j{d (190 (b)

2 Report Documentation Page Form Approved OMB No Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 06 APR REPORT TYPE 3. DATES COVERED to TITLE AND SUBTITLE Deposition of Crystalline Layers on Polymer Substrates Using Nanoparticles and Laser Nanoforming 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of Central Florida,CREOL, The College of Optics and Photonics,Orlando,FL, PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR S ACRONYM(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 11. SPONSOR/MONITOR S REPORT NUMBER(S) 14. ABSTRACT A method of forming crystalline semiconducting layers on low melting or low softening point substrates includes the steps of providing an aqueous solution medium including a plurality of semiconductor nanoparticles dispersed therein having a median size less than 10 nm, and applying the solution medium to at least one region of a substrate to be coated. The substrate has a melting or softening point of <200? C. The solution medium is evaporated and the at least one region is laser irradiated for fusing the nanoparticles followed by annealing to obtain a continuous film having a recrystallized microstructure. An article includes a polycrystalline semiconducting layer including a plurality of crystallites predominately in the size range of 2 to 50 f.1lll, and a substrate having a melting or softening point of <200? C. supporting the semiconducting layer. An average grain size of the crystallites is less at an interface proximate to the semiconducting layer as compared to an average grain size further away from the interface. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Same as Report (SAR) 18. NUMBER OF PAGES 17 19a. NAME OF RESPONSIBLE PERSON Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18

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