Electroluminescent porous silicon device with an external quantum efficiency greater than 0.1% under CW operation

Loni, A.; Simons, Andrew J.; Cox, T. I.; Calcott, P. D. J.; Canham, Leigh

doi:10.1049/el:19950831

Cited by 182 publications

(34 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Following several years of effort, efficiencies quoted for porous silicon are currently around the 10% mark for photoluminescence and 0.1% for electroluminescence. 13 Given the state of research into nanoclustered and nanocrystalline silicon, there is every reason to expect that the efficiencies quoted in this study can be greatly improved. As bulk silicon effectively exhibits no luminescence at room temperature, these results demonstrate luminescence enhancement due to the quantum confinement effects seen in nanoscale material.…”

Section: ͓S0003-6951͑98͒03330-0͔mentioning

confidence: 93%

Luminescence efficiency measurements of silicon nanoclusters

Kenyon

Trwoga

Pitt

et al. 1998

Applied Physics Letters

View full text Add to dashboard Cite

We present the results of what we believe to be the first study of the power efficiency of room temperature photoluminescence from thin films of silica containing silicon nanoclusters. Films were prepared by plasma enhanced chemical vapor deposition from silane and nitrous oxide precursors. Luminescence was excited using the 476 nm line of an argon-ion laser. We have measured power efficiencies for samples that exhibit luminescence solely due to radiative recombination of quantum confined excitons. Efficiencies around 0.04% are reported. © 1998 American Institute of Physics. ͓S0003-6951͑98͒03330-0͔Following Canham's report of visible luminescence from porous silicon, 1 there has been an explosion of interest in light emission from novel forms of nanoscale silicon. There have been a number of reports in the literature of visible and near-IR emission from silicon nanoclusters. [2][3][4][5][6] Typically, such clusters lie in the sub-100-Å diameter regime and exhibit a broad red luminescence band similar to that reported from porous silicon. Reports have been published of nanoclusters deposited onto silicon substrates and embedded within dielectric matrices such as silica. There has been much debate over the nature of the luminescence mechanism in this material and contradictory reports of its optical properties, but there is a growing consensus that, in common with porous silicon, quantum confinement of excitons within the nanoclusters plays a significant role. 7-10 Previous work by this group has addressed the nature of the luminescence mechanism and has indicated the presence of two distinct processes: radiative recombination of confined excitons within the silicon nanoclusters and defect luminescence from the surrounding matrix. 7,8 A single unique mechanism does not provide a good enough explanation of the luminescence properties of nanoscale silicon. However, whatever the mechanism, this remains a technologically important material as it makes a significant contribution to the search for a silicon-based light emitting material. For this reason, it is imperative to obtain measurements of luminescence efficiency from nanoclustered silicon. To date, despite the number of reports of luminescence from silicon nanoclusters, there have been no reported studies of luminescence efficiency from this class of material.In this letter we present the results of a study undertaken to measure photoluminescence power efficiencies of thin films of silica containing nanoclustered silicon. The films were produced by plasma enhanced chemical vapor deposition ͑PECVD͒: details of their growth can be found in Ref. 7. Films were 1-2 m thick and were grown on silicon substrates. Photoluminescence was excited using the 476 nm line of an argon-ion laser, and for the purposes of recording spectra luminescence was dispersed through a single-grating Bentham M300 monochromator and detected using a photomultiplier tube. Spectra were corrected for the spectral response of the optical system and the whole apparatus was computer controlled.For m...

show abstract

Section: ͓S0003-6951͑98͒03330-0͔mentioning

confidence: 93%

Luminescence efficiency measurements of silicon nanoclusters

Kenyon

Trwoga

Pitt

et al. 1998

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…2 There are now a large number of groups working on many aspects of porous silicon, from fundamental theory [3][4][5] to the production of prototype luminescent devices. [6][7][8] However, the recognized instability of the material may suggest that it is perhaps less suitable for general device use than was originally thought. Reduction in light output after prolonged exposure to the atmosphere and light-induced degradation continue to pose problems.…”

Section: Introductionmentioning

confidence: 99%

The origin of photoluminescence from thin films of silicon-rich silica

Kenyon

Trwoga

Pitt

et al. 1996

Journal of Applied Physics

206

View full text Add to dashboard Cite

We have carried out a study of the photoluminescence properties of silicon-rich silica. A series of films grown using plasma enhanced chemical vapor deposition over a range of growth conditions were annealed under argon at selected temperatures. Photoluminescence spectra were measured for each film at room temperature and for selected films at cryogenic temperatures. The photoluminescence spectra exhibit two bands. Fourier transform infrared and electron spin resonance spectroscopies were used to investigate bonding and defect states within the films. The data obtained strongly suggest the presence of two luminescence mechanisms which exhibit different dependencies on film growth conditions and postprocessing. We make assignments of the two mechanisms as ͑1͒ defect luminescence associated with oxygen vacancies and ͑2͒ radiative recombination of electron-hole pairs confined within nanometer-size silicon clusters ͑''quantum confinement''͒.

show abstract

“…Anisotropy of PS depends on the crystalline orientation of the silicon substrate. Birefringence has been reported in (100), (111) and (110) oriented PS [53,54,55,56,57]. In all these cases, the PS layer can be assumed to be uniaxial, and the direction of the optical axis to be normal to the surface for the (100) and (111) …”

Section: Dielectric Function and Refractive Indexmentioning

confidence: 99%

Porous Silicon

Ossicini¹,

Pavesi²,

Priolo³

2003

Springer Tracts in Modern Physics

View full text Add to dashboard Cite

In 1990 it was proposed that Si when rendered porous can be an efficient light emitting system, as efficient as many III-V semiconductor systems [1]. The reason for this was attributed to the low dimensionality of the surviving Si skeleton. In addition other effects were recognized: (1) the large photon extraction efficiency due to the decrease in the effective refractive index and (2) the confinement of the carriers in regions free of recombination centers. After this very surprising report, a huge number of papers was published trying to understand the optical properties of porous silicon (PS) and the physical mechanism at the heart of the large luminescence efficiency. Soon it was realized that PS is a very fragile and highly reactive material so that many of its properties are age dependent and unstable. Over the years, sizeable progress was made both in terms of improvement of its stability and in term of efficiency of the device. Microelectronics compatibility of PS was demonstrated and integration of driving circuits with a light emitting element was performed [2]. At the same time microcavities with improved light emission properties were demonstrated [3]. At the end of 2000 another paper shocked the silicon community: the report on light amplification or optical gain in silicon nanocrystals [4]. This paper raises big hopes of the development of a silicon laser even though it is not yet clear whether PS can be used as an active material.In this chapter we will try to review the most important results about the exploitation and the understanding of the properties of PS. The chapter is divided into six parts. The first introduces how porous silicon is made. The second is aimed to demonstrate that the structure of PS is a collection of nanometric objects that contribute to the light emission process. The relevant role of the surface chemistry is underlined. The third and fourth parts discuss the essential features of the absorption and luminescence of PS in order to discriminate between the models of the recombination mechanisms. The fifth presents recent progress in the field of electrical properties of PS. The section six is an overview of the application of PS in light emitting diodes.In the last few years various conference proceedings [5], review articles [6] and edited books [7] have been published on PS.

show abstract

Electroluminescent porous silicon device with an external quantum efficiency greater than 0.1% under CW operation

Cited by 182 publications

References 4 publications

Luminescence efficiency measurements of silicon nanoclusters

Luminescence efficiency measurements of silicon nanoclusters

The origin of photoluminescence from thin films of silicon-rich silica

Porous Silicon

Contact Info

Product

Resources

About