Visible light from aluminum-porous silicon Schottky junctions

Abstract

The fabrication technologies and the properties of light-emitting devices based on A 1-porous silicon (PS) Schottky junctions have been developed. Bright light emission, visible by the naked eye at normal daylight, is observed at the edge of the electrodes under reverse bias.The electroluminescence (EL) starting voltage is in the range 5-18 V, depending on the doping level of Si substrate. The current level at which the EL starts is around 1 mA for devices of 2.3 X 10 " 3 cm 2 area. The lighi emission intensity increases with increasing current density. EL spectra were broad, covering the whole visible range.The time stability was excellent for all tested devices; the EL intensity did not show remarkable changes, even after more than ten days of continuous light emission at voltages lower than thermal breakdown.

Electroluminescence from laser-grooved silicon

“…The spectrum covers almost the whole visible light range and has a peak at around 650 nm. This is similar to that of devices made from SP-Si [15,16], some por-Si [8,9] and also MIS structures showing carrier tunnelling [3], but not like that of reversebiased p-n junctions [1]. The visible EL, which was well reproducible in samples, always occurs in conditions when the top semitransparent metal is biased negatively.…”

“…The visible EL, which was well reproducible in samples, always occurs in conditions when the top semitransparent metal is biased negatively. This was also the case for SP-Si [15,16] and some por-Si [8,9]. This suggests the possibility that electrons are injected into the bulk materials from the surface metal.…”

“…Specially processed Si, such as porous Si (por-Si) [4] and spark-processed Si (SP-Si) [5], can also produce visible light emission. In the last few years, improved efficiency from por-Si-based visible-light-emitting diodes (LEDs) has been reported [6][7][8][9]. Though it is widely accepted that a quantum confinement effect [4] may cause a blue shift in the recombination radiation in por-Si, other explanations, for example, the existence of OH groups [10], have also been proposed.…”

Impact of thermal oxidation on the structural and optical properties of porous silicon microcavity

“…5 The third generation of devices with high efficiencies and long duration was based on post-etching oxidation. 6 Integration of porous silicon-based LED with conventional microelectronics circuitry has been demonstrated. 7 Highly sensitive photodetectors and optical logic gates have been fabricated from porous silicon.…”

Preparation and Characterisation of Metallic Thin Films for Electroluminescent Devices Based on Porous Silicon

“…The peak wavelengths depend on the metal contact, and can be varied in the range 455 nm (indium) to 700 nm (antimony). One group has obtained a structure in which optically transmitting windows are produced in an opaque aluminium contact layer by anodically oxidising the aluminium to form transparent aluminium oxide [11][12][13][14][15]. The synthesis of the main PS solid contact preparation methods is presented below.…”