Si-based Blue Light Emitting Diode

Award Information
Agency:
Department of Defense
Branch
Missile Defense Agency
Amount:
$74,511.00
Award Year:
1993
Program:
SBIR
Phase:
Phase I
Contract:
n/a
Agency Tracking Number:
19647
Solicitation Year:
n/a
Solicitation Topic Code:
n/a
Solicitation Number:
n/a
Small Business Information
Spire Corp.
One Patriots Park, Bedford, MA, 01730
Hubzone Owned:
N
Socially and Economically Disadvantaged:
N
Woman Owned:
N
Duns:
n/a
Principal Investigator:
Fereydoon Namavar, Scd
(617) 275-6000
Business Contact:
() -
Research Institution:
n/a
Abstract
UNDER AN ONGING SDIO-FUNDED SBIR PROGRAM, SPIRE RECENTLY DEMONSTRATED THE FIRST Si-BASED VISIBLE LIGHT-EMITTING DIODES (LED), OBTAINING COLORS RANGING FROM RED THROUGH YELLOW. THESE Si DEVICES WERE PRODUCED AS NANODIMENSIONAL STRUCTURES FROM P-TYPE SUBSTRATES BY ELECTROCHEMICAL ETCHING. THE SHORTER WAVELENGTHS RESULTED FROM REDUCING THE STRUCTURE SIZE TO THE 1-2 NM LEVEL. HOWEVER, CALCULATIONS OF THE CONFINEMENT ENERGIES OF ELECTRONS AND HOLES IN Si NANOSTRUCTURES INDICATE THAT THE CRYSTAL DIMENSIONS REQUIRED FOR BLUE EMISSION ARE GENERALLY TOO SMALL TO BE STABLE OVER EXTENDED PERIODS. WE PROPOSE THAT THE CONSTRAINTS ON MICROCRYSTALLINE DIMENSIONS FOR PRODUCING BLUE LEDs CAN BE RELAXED BY CREATING ALLOYS OF Si WHICH INSTRINSICALLY POSSESS LARGER ENERGY GAPS. SIGNIFICANTLY, SINCE CRYSTALLINE CARBON (DIAMOND) HAS A LARGE BANDGAP (5.5 eV), ALLOYS OF SEVERAL PERCENT C IN Si WILL READILY INCREASE THE BASE BANDGAP; HOWEVER, MISMATCHES IN UNIT CELL DIMENSIONS WILL BE DETRIMENTAL, UNLESS GERMANIUM ATOMS ARE ALSO INTRODUCED TO COMPENSATE. WE PREDICT THAT THE OPTICAL EMISSION PROPERTIES WILL BE AFFECTED PREDOMINATELY BY C, ALLOWING FORMATION OF A NEW MATERIAL EXHIBITING QUANTUM CONFINEMENT EFFECTS PLUS DIMENSIONAL STABILITY. IN PHASE I, WE SHALL USE SPIRE'S PROVEN NON-EQUILIBRIUM DEPOSITION CONDITIONS, ALREADY APPLIED TO Si(1-x)Ge(x), TO ASSURE THE FORMATION OF Si(1-x-y)Ge(x)C(y) ALLOYS, 0,x,y<5%, WITHOUT SUFFERING THE FORMATION OF UNDESIRABLE SECOND PHASES, AND DEMONSTRATE BLUE PHOTOLUM-INESCENCE IN ETCHED STRUCTURES. WE WILL DEMONSTRATE BLUE ELECTROLUM-INESCENCE IN POROUS SiGeC-BASED DEVICES IN PHASE II.

* information listed above is at the time of submission.

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