POROUS POLYSILICON LIGHT EMITTERS FOR MONOLITHICALLY-INTEGRATED THIN FILM ELECTROLUMINESCENT (FTEL) DISPLAY PANELS

RESEARCHERS ARE INVESTIGATING DEMONSTRATION OF VISIBLE ELECTRO-LUMINESCENT (EL) DEVICES FABRICATED ON POROUS POLYSILICON THIN FILM ON GLASS SUBSTRATES FOR LOW-COST, MONOLITHICALLY-INTEGRATED, ALL-SILICON FLAT-PANEL DISPLAYS. RESEARCHERS RECENTLY FABRICATED THE FIRST SI-BASED LIGHT-EMITTING DIODES CONFIGURED AS HETEROJUNCTIONS BETWEEN A P-TYPE POROUS SI AND AN N-TYPE TRANSPARENT SEMICONDUCTOR (INDIUM-TIN-OXIDE). QUANTUM CONFINEMENT IN SI NANOSTRUCTURES IS THE KEY TO THE LUMINESCENCE OF THESE DEVICES. THESE LEDS ARE CAPABLE OF EMITTING YELLOW, ORANGE, AND RED LIGHT, AND THE FABRICATION OF A POROUS SI-BASED BLUE LED IS UNDERWAY. ALTHOUGH MOST PREVIOUS WORK ON POROUS SILICON DEVICES HAS EMPLOYED BULK SI MATERIALS RATHER THAN SI THIN FILMS, RECENT WORK HAS SHOWN THAT BRIGHT VISIBLE LIGHT CAN ALSO BE OBTAINED FROM POROUS STRUCTURES FORMED ON POLYCRYSTALLINE SILICON THIN FILMS DEPOSITED ON GLASS SUBSTRATES. THIS DEVELOPMENT MAY ENABLE THE CREATION OF A NOVEL THIN FILM ELECTROLUMINESCENT (TFEL) TECHNOLOGY BASED ON POROUS POLYSILICON FILMS. SUCH A TECHNOLOGY WOULD BE NOT ONLY MORE ECONOMICAL AND PRACTICAL THAN CONVENTIONAL PRACTICE, BUT COULD ALSO OFFER THE MONOLITHIC INTEGRATION OF DISPLAY ELEMENTS WITH THIN FILM TRANSISTOR (TFT) CHIP-ON-GLASS DRIVER CIRCUITRY ON A SINGLE POLYCRYSTALLINE SI LAYER.