Accession Number:

ADA341656

Title:

Development of Quantum Dot Materials for Optical Devices by the Sol-Gel Method.

Descriptive Note:

Final rept. 1 Jun 94-30 Jan 98,

Corporate Author:

CALIFORNIA UNIV LOS ANGELES DEPT OF MATERIALS SCIENCE AND ENGINEERING

Personal Author(s):

Report Date:

1998-02-01

Pagination or Media Count:

28.0

Abstract:

This Final Technical Report presents a summary of the research conducted from June, 1994 to January, 1998 on the development of semiconductor quantum dot materials prepared by a sol-gel method. The process involved the preparation of a sol-gel liquid solution with a chemical composition corresponding to that of a sodium borosilicate glass, the addition of a cadmium salt to the solution, the formation of a porous gel, the conversion of the cadmium salt to CdS and the densification of the gel into a glass at around 5OO deg C. By systematic variation of processing conditions OdS quantum dots OD of uniform size and size distribution were prepared. For the first time, optical gains were achieved at room temperature. By ion-exchange of K for Na, waveguides were fabricated. The OdS particles were shown to be single crystals of about 4oA in dimension. Techniques were developed to prepare CdTe and PbS ODs in sodium borosilicate glass. Not only are the Bohr radii of PbS and OdTe much larger than that of OdS, which will give more efficient ODs samples, but the beginning of a systematic study of these three semiconductors would shed light on the presently unknown effects of the relatively large surface areas of QEs. A search of the literature revealed that the semiconductor SbSl is also a ferroelectric. It is theorized that an electric field induced dipole in SbSl would act to pin down the exciton created by a laser beam. Thus, longer life-times of the electron-hole pair are possible. Preliminary work has resulted in the successful preparation of SbSl ODs in the same sodium borosilicate glass. Verification of the behavior of SbSl now awaits further research.

Subject Categories:

  • Inorganic Chemistry
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE