Efficient visible electroluminescence from highly porous silicon under cathodic bias

Canham, Leigh; Leong, Wai Yie; Beale, M.I.J.; Cox, T. I.; Taylor, L. L.

doi:10.1063/1.108127

Cited by 167 publications

(79 citation statements)

References 13 publications

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“…1,2 The emission from n-type porous silicon electrodes in contact with an acidic solution containing S 2 O 8 2-is efficient and in the visible region of the spectrum. One of the interesting aspects of the luminescence is the shift of the emission maximum to higher energies as the potential is scanned to negative values.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Peroxodisulfate at Porous and Crystalline Silicon Electrodes: An Anomaly

1996

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Electroluminescence from n-type porous silicon can be generated in solution by reduction of peroxodisulfate. It has been assumed that the SO 4•-radical ion, formed in the first reduction step, injects a hole into the valence band of the porous semiconductor. The hole should subsequently undergo radiative recombination with a conduction band electron. Using two techniques, viz., photocurrent quantum efficiency measurements with p-type porous and crystalline silicon electrodes and minority carrier injection studies with the "transistor technique", we found that the reduction of peroxodisulfate is, however, not always accompanied by hole injection. The silicon results are compared with results obtained on GaAs electrodes.

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Section: Introductionmentioning

confidence: 99%

Reduction of Peroxodisulfate at Porous and Crystalline Silicon Electrodes: An Anomaly

1996

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“…9 Much higher efficiencies were obtained using a liquid electrolyte junction which contacts the whole porous structure. [10][11][12] The mechanism of the strong visible emission from n-type porous silicon is thought to be similar to that for conventional semiconductors. Electron capture from the valence band, i.e., hole injection, is achieved by a strong oxidizing agent ͑electron acceptor͒ in the solution.…”

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confidence: 99%

Electroluminescence from porous silicon due to electron injection from solution

Kooij

Despo

Kelly

1995

Applied Physics Letters

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We report on the electroluminescence from p-type porous silicon due to minority carrier injection from an electrolyte solution. The MV ϩ• radical cation formed in the reduction of divalent methylviologen is able to inject electrons into the conduction band of crystalline and porous silicon. The electrochemistry of this redox process at silicon electrodes is briefly described, and electroluminescence due to recombination of the injected electrons with holes from the substrate is described. The results are discussed in terms of a semiconductor model. © 1995 American Institute of Physics.One of the main reasons for the extensive research on porous silicon is the prospect of integrating optical functions into all-silicon devices. To make a device capable of showing electroluminescence ͑EL͒, electrons and holes have to be injected into the porous silicon structure. Radiative recombination of these carriers will give rise to light emission. The first luminescent solid state devices based on this material 1-3 consisted of a porous layer on a crystalline substrate. A semitransparent Au or transparent conducting oxide electrode was deposited on top of the porous layer. These devices were reported to have very low quantum efficiencies (Ͻ10 Ϫ6 ) and require high operating voltages. More recently, different designs 4,5 and better contact materials 6-8 have led to some improvement in the electrical and luminescent properties. The reasons for the low EL efficiency are not understood, but it has been suggested that the ease with which carriers are injected into luminescent states and the transport mechanisms in the porous silicon play an important role. 9Much higher efficiencies were obtained using a liquid electrolyte junction which contacts the whole porous structure. [10][11][12] The mechanism of the strong visible emission from n-type porous silicon is thought to be similar to that for conventional semiconductors. Electron capture from the valence band, i.e., hole injection, is achieved by a strong oxidizing agent ͑electron acceptor͒ in the solution. At appropriate bias the injected holes recombine with electrons from the conduction band. If this recombination is radiative, EL characteristic of the semiconductor can be observed. 13A similar mechanism should hold for p-type semiconductors, only now electron injection into the conduction band is required. This is possible if the occupied energy levels of the redox couple in the solution overlap with the conduction band of the semiconductor. Thus, a strong reducing agent ͑electron donor͒ has to be used. To our knowledge there have been no reports of EL from p-type porous silicon due to minority carrier injection by a reducing agent in solution.14 Light emission during anodic oxidation of p-type porous silicon in indifferent electrolyte has been reported. 15 This has been attributed to electrons released during oxidation of Si-H surface species or of Si-Si bonds. However, this explanation may be suspect as luminescence is also observed under similar conditions at n-type porous...

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“…[8]. The capacitance of PSi layer depends on its morphological properties since it decreases with the increasing thickness of the layer [9].…”

Section: Electrical Propertiesmentioning

confidence: 99%

Study of Electrical Properties of Photodetector

Mousa¹,

Nawfal²

2017

JEES

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In this paper porous silicon sample that can be used as a photodetector was prepared at fixed etching time of 15min and different etching current density (15, 17, 19 and 21) mA/cm 2 . Electrical properties of Al / PSi / p-Si /Al photodetector were studied. We found that the I-V characteristics dependence of the etching current density relates to the PSi pores development, where the pore diameter in PSi structure might get enlarged due to the enhancement of the etching current density. The ideality factor ranges around (6.8-4.2) while the barrier height decreased with the increasing etching current density and the etching time as the interface layer between PSi/c-Si has large amount of pinning. Then the C-V characteristics of the sandwich structure are described. When the etching current densities are increased, it reduces the capacitance of the PSi layer. It thus increases the thickness of the depletion region which in turn results in development of built-in potential.

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Efficient visible electroluminescence from highly porous silicon under cathodic bias

Cited by 167 publications

References 13 publications

Reduction of Peroxodisulfate at Porous and Crystalline Silicon Electrodes: An Anomaly

Reduction of Peroxodisulfate at Porous and Crystalline Silicon Electrodes: An Anomaly

Electroluminescence from porous silicon due to electron injection from solution

Study of Electrical Properties of Photodetector

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