Visible luminescence from silicon surfaces microstructured in air

Wu, Claudia; Crouch, Catherine H.; Zhao, Li; Mazur, Eric

doi:10.1063/1.1504868

Cited by 90 publications

(59 citation statements)

References 19 publications

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“…This class of materials is being studied for potential applications in photovoltaics, 10,11 photodetectors, 5,12 and light emitters. 13,14 Here, we report remarkable enhancement of both the range and magnitude of optoelectronic response exhibited by photodiodes with optically flat surfaces prepared by ion implantation with sulfur or selenium ions followed by nanosecond pulsed laser melting. 6 750 lm thick double-side polished p-type Si(001) wafers with resistivity 10-30 X cm were ion implanted at room temperature with either 95keV 32 .…”

mentioning

confidence: 99%

Extended infrared photoresponse and gain in chalcogen-supersaturated silicon photodiodes

Said¹,

Recht²,

Sullivan³

et al. 2011

Applied Physics Letters

105

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Highly supersaturated solid solutions of selenium or sulfur in silicon were formed by ion implantation followed by nanosecond pulsed laser melting. n+p photodiodes fabricated from these materials exhibit gain (external quantum efficiency >3000%) at 12 V of reverse bias and substantial optoelectronic response to light of wavelengths as long as 1250 nm. The amount of gain and the strength of the extended response both decrease with decreasing magnitude of bias voltage, but >100% external quantum efficiency is observed even at 2 V of reverse bias. The behavior is inconsistent with our expectations for avalanche gain or photoconductive gain.

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mentioning

confidence: 99%

Extended infrared photoresponse and gain in chalcogen-supersaturated silicon photodiodes

Said¹,

Recht²,

Sullivan³

et al. 2011

Applied Physics Letters

105

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“…The similar clustering structures corresponding to the second stage of banded dots have been previously reported for the Si͑100͒ surface induced by laser irradiation in He ambient 12 and in vacuum, 17 and the larger dots may act as a precursor of known larger bodies, such as microcolumns 10,14 and cones. 16 The resultant LIPSS-dots are considered to form because atomic clusters locally ablated from the surface redeposit as debris and are then irradiated again by subsequent laser ͑Color online͒ ͑a͒ SEM images of LIPPS-dots on Si͑100͒ surface after multiple numbers of laser shots in a low-pressure chamber ͑1.33 Pa͒, respectively, 1000, 1500, 3000, and 4000 ͑from left to right͒ at repetition rate of 2 Hz and with energy density of 1.24 kJ/ m 2 . Laser incidence was normal to surfaces and polarization was horizontal to images.…”

Section: Resultsmentioning

confidence: 99%

“…8 Conical structures 15 and microcolumns 10,14 on a silicon surface produced by multiple laser pulses have the potential to be used in photodetectors because of their capability to absorb incident light over a wide range of wavelengths. 15,16 Similarly, the luminescent Si-nanocluster arrays fabricated by laser irradiation are also anticipated to be used in quantum dot devices. 17,18 We report a laser-induced periodic surface structure of epitaxially grown dot like protrusions ͑hereafter, denoted as LIPSS-dots͒ on a Si surface with known regular-ripples ͑hereafter, denoted as conventional-LIPSS [19][20][21][22] ͒ induced by nanosecond pulsed laser irradiation at a low laser energy density, typically less than 5 kJ/ m 2 .…”

Section: Introductionmentioning

confidence: 99%

In situ observation of self-organizing nanodot formation under nanosecond-pulsed laser irradiation on Si surface

Watanabe

Yoshida

Kayashima

et al. 2010

Journal of Applied Physics

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An in situ observation of the formation of a laser-irradiation-induced nanodot array on a Si surface was performed using a pulsed-laser-equipped high-voltage electron microscope ͑laser-HVEM͒. Under multiple nanosecond ͑ns͒ pulsed laser irradiation shots, atomic clusters were first formed and distributed on the surface in order to grow them epitaxially into protruded dots with diameters of ten nanometers or less. This is followed by their diffusion induced by successive laser shots to cannibalize and merge them into a ripple line with aligned, larger dots. We conclude that the present subwavelength two-dimensionally-ordered nanodot array is formed by self-organization under pulsed laser irradiation.

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“…native oxide layer that grows on the surface after texturing, but the air sample contains two orders of magnitude more oxygen than the other samples. The high oxygen content and further analysis using Rutherford backscattering spectrometry and transmission electron microscopy suggest that a silicon rich layer of silica, SiO x (x<2) [38], is formed. The amount of oxygen in the SF 6 , Cl 2 , and N 2 samples is correlated with surface area (roughness).…”

Section: Surface Layer Structure and Compositionmentioning

confidence: 99%

“…These applications are only a subset of the applications that we are currently investigating or plan to investigate. Among the other applications are photoluminescent surfaces [38], micromanipulation of biomagnetic material, and increased efficiency for drug delivery. We also demonstrated superhydrophylic behavior for microstructured surfaces, and alternatively, superhydrophobic behavior for microstructured surfaces coated with teflon.…”

Section: Future Directionsmentioning

confidence: 99%

Microtextured Silicon Surfaces for Detectors, Sensors & Photovoltaics

Carey¹,

Mazur²

2005

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Executive SummaryWith support from this award we studied a novel silicon microtexturing process and its application in silicon-based infrared photodetectors. By irradiating the surface of a silicon wafer with intense femtosecond laser pulses in the presence of certain gases or liquids, the originally shiny, flat surface is transformed into a dark array of microstructures. The resulting microtextured surface has near-unity absorption from near-ultraviolet to infrared wavelengths well below the band gap. The high, broad absorption of microtextured silicon could enable the production of silicon-based photodiodes for use as inexpensive, room-temperature multi-spectral photodetectors. Such detectors would find use in numerous applications including environmental sensors, solar energy, and infrared imaging.The goals of this study were to learn about microtextured surfaces and then develop and test prototype silicon detectors for the visible and infrared. We were extremely successful in achieving our goals. During the first two years of this award, we learned a great deal about how microtextured surfaces form and what leads to their remarkable optical properties. We used this knowledge to build prototype detectors with high sensitivity in both the visible and in the near-infrared. We obtained room-temperature responsivities as high as 100 A/W at 1064 nm, two orders of magnitude higher than standard silicon photodiodes. For wavelengths below the band gap, we obtained responsivities as high as 50 mA/W at 1330 nm and 35 mA/W at 1550 nm, close to the responsivity of InGaAs photodiodes and five orders of magnitude higher than silicon devices in this wavelength region.The following Project Summary includes: Summary of important resultsPrior to receipt of this contract, we developed a process for microtexturing silicon surfaces with laser-assisted etching [1, 2]. The silicon sample is irradiated with a train of high-power ultrashort (100 fs) laser pulses in the presence of SF 6 or Cl 2 . Where the laser strikes the surface, material is etched away in a pattern of conical spikes, with the spike tips at the level of the unetched surface and the spike bases tens of microns below the surface. The surrounding non-irradiated silicon is unaffected, so areas as small as tens of microns on a side can be made. Figure 1 shows a scanning electron micrograph of a microtextured silicon surface.After etching, the silicon surface appears black to the eye (see Figure 2), and the surface absorbs over 90% of incident light from 0.25 µm to 2.5 µm [3]. Flat crystalline silicon absorbs only about 65% of incident light for wavelengths shorter than 1 µm, and absorbs less than 20% at longer wavelengths, with very low absorptance from 1.1 to 1.4 µm. Creation of a prototype microtextured silicon based p-i-n detector.Much of the work done in Year One and Year Two characterized the effects of laser fluence, shot number, gas pressure, and ambient gas on the absorption properties of microtextured silicon [4][5][6][7]. Using this data, we attempted to make...

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Visible luminescence from silicon surfaces microstructured in air

Cited by 90 publications

References 19 publications

Extended infrared photoresponse and gain in chalcogen-supersaturated silicon photodiodes

Extended infrared photoresponse and gain in chalcogen-supersaturated silicon photodiodes

In situ observation of self-organizing nanodot formation under nanosecond-pulsed laser irradiation on Si surface

Microtextured Silicon Surfaces for Detectors, Sensors & Photovoltaics

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