Mechanism of optical absorption enhancement of surface textured black silicon

Jiang, Jing; Li, Shibin; Jiang, Yadong; Wu, Zhiming; Xiao, Zhanfei; Su, Yuanjie

doi:10.1007/s10854-012-0756-z

Cited by 18 publications

(12 citation statements)

References 10 publications

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“…According to this graded index layer model, it is reasonable to expect that any tip‐like nanostructures, probably microstructures as well, such as the silicon nanocone arrays or micropyramid arrays, also have this THz antireflective effect. Furthermore, except silicon substrate studied here, other typical semiconductors such as germanium (Ge) and gallium arsenide (GaAs) are also promising candidates for this kind of optical‐driven THz modulator .…”

Section: Theoretical Modelmentioning

confidence: 99%

Terahertz Modulators Based on Silicon Nanotip Array

Shi

Cao

Wen

et al. 2017

Advanced Optical Materials

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As an attractive applications of terahertz (THz) radiation, imaging with THz technique stands at the focus of current interest. THz spatial modulators are key issue for fast imaging with a single detector. Here, for the first time, the silicon nanotip (SiNT) arrays are reported that can be utilized as antireflection layers for the THz wave to achieve a low‐loss and spectrally broadband optical‐driven THz modulator. Compared with the modulator fabricated with bare silicon, a 2–3‐time larger modulation depth is achieved in SiNT modulator. Moreover, it is found that the intrinsic THz transmission of SiNT is as high as 90%, which is much higher than that of bare silicon. The theoretical simulation results reveal that a strong antireflection effect induced from SiNT layer plays a crucial role in enhancing the properties of modulator. The SiNT‐based optical‐driven THz modulator with low loss and high modulation depth is promising for potential application to THz imaging.

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Section: Theoretical Modelmentioning

confidence: 99%

Terahertz Modulators Based on Silicon Nanotip Array

Shi

Cao

Wen

et al. 2017

Advanced Optical Materials

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“…The microtextured surface was fabricated by anisotropic wet chemical etching technique [ 27,28 ] on n‐Si (100) wafers with resistivity ρ ≈ 1000 Ω·cm and thickness t ≈ 520 µm. The anisotropic response of Si to KOH results in different etching rate for different crystal face, where (100) shows the fastest while (111) the slowest, [ 28 ] and eventually producing pyramid‐resembled microstructures on Si surface. Figure a shows a typical scanning electron microscope (SEM) image of the textured Si with numerous square micropyramids.…”

Section: Resultsmentioning

confidence: 99%

“…The micropyramid array structures could greatly reduce optical reflectivity due to the multiple geometric reflection. [ 28,29 ] As shown in Figure 1c, the optical reflectance from the Si‐MPA sample is significantly reduced in comparison with that of the bare Si over a wide wavelength range from 300 to 1050 nm. It can be seen that with the decrease of light wavelength, the reflectance of bare Si notably increases while that of Si‐MPA almost keeps constant.…”

Section: Resultsmentioning

confidence: 99%

High‐Performance Photo‐Induced Spatial Terahertz Modulator Based on Micropyramid Silicon Array

Wen

Yang

et al. 2020

Adv Materials Technologies

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Reconfigurable conductive pattern created by photoexcitation of high‐resistivity semiconductor provides a powerful approach to realize broadband spatial terahertz modulators (STM), which are highly demanded for constructing cost‐effective and compact terahertz (THz) system. Here a high performance all‐optical STM is proposed and realized based on silicon micropyramid arrays (Si‐MPA), which not only enhances the light harvesting across a broad wavelength range, but also greatly increases the active area for THz modulation. Upon illuminating the Si‐MPA by light with various wavelengths, modulation depth (MD) of four times larger than that of bare silicon is achieved. A maximum MD of 93.8% is obtained under 638 nm laser with a low power density of 1 W cm−2. Reconfigurable THz imaging system based on the Si‐MPA modulator and a single‐element detector is constructed, with which precise THz beam mapping and fast real‐time imaging with 225 pixels are demonstrated. This Si‐MPA‐based STM with large MD at low illumination power density is promising for many THz applications including imaging, beam shaping, holographic projection, etc.

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“…The reflectance ( R ) and transmittance ( T ) were measured with an UV‐VIS‐NIR spectrophotometer equipped with an integrating sphere detector (PG2000‐Pro‐EX and NIR2500) from 0.25 to 2.5 µm. The absorptance ( A ) was calculated by formula: A = 1 −R−T . Hitachi S‐3400 scanning electron microscope (SEM) was used to characterize the surface morphologies of hyper‐doped silicon.…”

Section: Methodsmentioning

confidence: 99%

“…Silicon is the most prevalent semiconductor used in microelectronics and photonics. But the band gap (1.12 eV) of silicon limits the absorption of the incident photons with wavelength longer than 1100 nm. Previous works indicate that the absorption of chalcogen hyper‐doped silicon for above‐band gap and below‐band gap are enhanced up to 90% before annealing , which makes sulfur hyper‐doped silicon a promising material for NIR optical devices, such as FFT‐CCD (Full Frame Transfer) area image sensor of HAMAMATSU and CMOS photodetector of SiOnyx.…”

Section: Introductionmentioning

confidence: 99%

High near infrared absorption of hyper‐doped silicon induced by co‐doping of sulfur and nitrogen

Xuan

Zhang

Liu

et al. 2016

Physica Status Solidi (a)

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In this paper, we investigate the dependence of NIR absorption of hyper-doped silicon on different sulfur and nitrogen doping ratio. With different molecular proportion of N 2 and SF 6 background gas, femtosecond laser irradiation was used to implant co-doping of sulfur and nitrogen into silicon. The hyper-doped silicon presents high absorption properties in NIR and visible range. The results of first-principles calculations demonstrate the high absorption in NIR is ascribed to the induced impurity energy levels in hyper-doped silicon. The nitrogen doping process improves the crystallinity in the doped layer because the doped nitrogen repairs defects in silicon lattices. Given the thermal stability of nitrogen, the co-doping dopants limit the diffusion of sulfur during the annealing process. The co-doping process proposed in this paper provides a method to fabricate high performance NIR silicon optoelectronic device.

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Mechanism of optical absorption enhancement of surface textured black silicon

Cited by 18 publications

References 10 publications

Terahertz Modulators Based on Silicon Nanotip Array

Terahertz Modulators Based on Silicon Nanotip Array

High‐Performance Photo‐Induced Spatial Terahertz Modulator Based on Micropyramid Silicon Array

High near infrared absorption of hyper‐doped silicon induced by co‐doping of sulfur and nitrogen

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