Accession Number : ADP008158

Title :   Emically-Induced Shifts in the Photoluminescence Spectra of Porous Silicon,

Corporate Author : TEXAS UNIV AT AUSTIN DEPT OF ELECTRICAL AND COMPUTER ENGINEERING

Personal Author(s) : Li, K.-H. ; Tsai, C. ; Campbell, Joe C. ; Hance, B. K. ; White, J. M.

Report Date : APR 1992

Pagination or Media Count : 2

Abstract : The realization of practical, Si-based light-emitting devices would have a significant impact on numerous key technologies such as optoelectronic integrated circuits, optical interconnects, optical memories and logic, and advanced display systems. Previously, Si has exhibited extremely weak emission owing to its indirect bandgap. Recently, however, observations of efficient room-temperature, visible photoluminescence (PL) from porous silicon, have stimulated research and extensive debate on the physical mechanisms responsible for this luminescence. To date, the explanations that have been proffered include (1) quantum size effects in highly porous Si, (2) the formation of wide-bandgap material such as a-Si:Hx 41 or SILOXENE 5 during anodization, and (3) a local increase in the bandgap energy due to the presence of dihydride species on the surface. Previously, we have utilized photoluminescence (PL) and transmission Fourier-transform infrared (FTIR) spectroscopy to demonstrate that hydrogen desorption from the dihydride surface species on porous Si is correlated to a decrease in the emission intensity. In this paper, we show that changes in the surface chemistry achieved by changing the composition of the electrolyte-in which the anodized wafer is immersed result in large shifts in the PL spectra Using this approach we have repeatedly cycled the emission between red and green. These results are inconsistent with a quantum-confinement interpretation for the emission process.

Descriptors :   *PHOTOLUMINESCENCE, *OPTICAL CIRCUITS, DESORPTION, DISPLAY SYSTEMS, ELECTROLYTES, EMISSION, ENERGY, HYDROGEN, IMPACT, INTEGRATED CIRCUITS, INTENSITY, LIGHT, LOGIC, LUMINESCENCE, MATERIALS, OBSERVATION, ROOM TEMPERATURE, SILICON, SPECTRA, SPECTROSCOPY, SURFACE CHEMISTRY, SURFACES, TEMPERATURE, WAFERS.

Subject Categories : Electrooptical and Optoelectronic Devices

Distribution Statement : APPROVED FOR PUBLIC RELEASE