Silicon Light Emitters: Preparation, Properties, Limitations, and Integration with Microelectronic Circuitry

Abstract

Starting with Canham’s discovery in 1990 that porous silicon (PSi) can emit bright light in the visible range of the spectrum, there has been a strong interest in silicon light emitters. PSi and other light-emitting forms of silicon contain nanostructures or crystallites in the nanometer size range. Throughout most of the 1990’s, the intense visible luminescence from nanoscale silicon crystallites has been a source of numerous investigations and considerable debate. Today, most of the controversies have been put to rest. However, much less has been written about nanoscale Si light-emitting devices, in part because some of their characteristics are less than ideal and not well understood. This paper reviews the status of nanoscale silicon light emitters. It starts with a survey of the manufacturing methods used to produce nanoscale Si. Next, key physical, optical, electrical, and structural properties of nanoscale Si are examined. The fabrication of electroluminescent devices (LEDs) is then discussed. We focus on the stability, efficiency, speed, and spectral characteristics of nanoscale Si light emitters. Recent results obtained on microcavity PSi LEDs and 1.5μm LEDs produced by doping PSi with erbium are discussed. Finally, the integration of PSi LEDs with microelectronic circuitry is reported and the prospects for practical devices are briefly examined.