Semiconductor meta-surface based perfect light absorber

Liu, Guiqiang; Nie, Yi-you; Fu, Guolan; Liu, Xiaoshan; Liu, Yi; Tang, Li; Liu, Zhengqi

doi:10.1088/1361-6528/aa6613

Cited by 35 publications

(32 citation statements)

References 46 publications

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“…Therefore, it can be deduced that the integration of a metallic layer underneath these semiconductor nanounits can intensify their absorption characteristics. This has been proved in many different nanounits' shapes including nanorings, nanoholes, nanopatches, and nanogratings . In these designs, the Mie resonances supported by the top semiconductor nanounits are superposed with FP cavity modes of the planar design.…”

Section: Light Trapping Schemesmentioning

confidence: 91%

Semiconductor Thin Film Based Metasurfaces and Metamaterials for Photovoltaic and Photoelectrochemical Water Splitting Applications

Ghobadi

Özbay

2019

Advanced Optical Materials

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throughput and large-scale compatibility. The photoactive material is generally composed of single or multiple semiconductor layers responsible for harvesting solar energy. This harvested solar irradiation can be used to generate electricity using photovoltaic (PV) devices, or it can be converted to chemical energy in the form of hydrogen which is the case for photoelectrochemical water splitting (PEC-WS). In both PV and PEC-WS applications, the ultimate goal is to establish an efficient photon capturing and electron collecting scheme to generate a huge number of photocarriers (including electron-hole pairs) with rational carrier dynamics (efficient charge generation, separation, and collection). This means that the device should be optically thick enough to generate high carrier's density and electrically thin enough to collect photogenerated carrier before they recombine. When light impinges a semiconductor surface, a part of the light is reflected back due to the mismatch between the air and the semiconductor layer refractive index. The rest will propagate within the bulk until it is fully absorbed by the semiconductor slab. The optical penetration depth (LPD) is defined as the depth at which the incident power falls to 1/e (≈37%) of its input value. This parameter differs from one semiconductor to another and it depends on the extinction coefficient (κ) of the In both photovoltaic (PV) and photoelectrochemical water splitting (PEC-WS) solar conversion devices, the ultimate aim is to design highly efficient, low cost, and large-scale compatible cells. To achieve this goal, the main step is the efficient coupling of light into active layer. This can be obtained in bulkysemiconductor-based designs where the active layer thickness is larger than light penetration depth. However, most low-bandgap semiconductors have a carrier diffusion length much smaller than the light penetration depth. Thus, photogenerated electron-hole pairs will recombine within the semiconductor bulk. Therefore, an efficient design should fully harvest light in dimensions in the order of the carriers' diffusion length to maximize their collection probability. For this aim, in recent years, many studies based on metasurfaces and metamaterials were conducted to obtain broadband and near-unity light absorption in subwavelength ultrathin semiconductor thicknesses. This review summarizes these strategies in five main categories: light trapping based on i) strong interference in planar multilayer cavities, ii) metal nanounits, iii) dielectric units, iv) designed semiconductor units, and v) trapping scaffolds. The review highlights recent studies in which an ultrathin active layer has been coupled to the above-mentioned trapping schemes to maximize the cell optical performance.

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Section: Light Trapping Schemesmentioning

confidence: 91%

Semiconductor Thin Film Based Metasurfaces and Metamaterials for Photovoltaic and Photoelectrochemical Water Splitting Applications

Ghobadi

Özbay

2019

Advanced Optical Materials

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“…Thus, metamaterials have attracted wide attention in recent 10 years in the field of miniaturization antenna, super resolution imaging, high sensitive detector, electromagnetic wave absorber, electromagnetic invisibility, and so on . Particularly, metamaterial absorbers have an important role in all sorts of applications, including imaging, detection, solar cell, and stealth technology . The metamaterial absorbers are based on the electromagnetic resonances by selecting different structures and correspondingly reasonable physical dimensions of the device, thereby achieving the absorption function at a specific frequency band .…”

Section: Introductionmentioning

confidence: 99%

“…21,22 Particularly, metamaterial absorbers have an important role in all sorts of applications, including imaging, detection, solar cell, and stealth technology. [23][24][25][26][27][28][29][30] The metamaterial absorbers are based on the electromagnetic resonances by selecting different structures and correspondingly reasonable physical dimensions of the device, thereby achieving the absorption function at a specific frequency band. 23 Therefore, by adjusting the structure and size of one unit, the metamaterials absorbers can achieve high absorption rate in different wavelengths such as microwave, terahertz, infrared, and visible light, which makes up for the deficiency of natural materials.…”

Section: Introductionmentioning

confidence: 99%

Polarization‐independent multiband metamaterials absorber by fundamental cavity mode of multilayer microstructure

Fang

Peng

et al. 2019

Micro & Optical Tech Letters

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We propose a multiband metamaterial absorber consisting of silicon brick array on metal substrate in infrared range. Using the regular hexagon array of silicon bricks, the absorption rate can reach to 90% over the bandwidth of 100 nm, and four absorption peaks with the absorption rate of more than 98% can be obtained. The absorber is independent on polarization angle. The multiband absorption performance can be attributed to primary cavity mode and Mie resonance in silicon bricks. Importantly, when the all‐dielectric silicon bricks are replaced by metal‐dielectric‐metal sandwich structure, the absorption rate above 75% with the bandwidth of more than 200 nm in the absorber can be realized, and it is polarization‐insensitive. The absorption peaks are increased to obtain broadband absorption. Our designed sandwich microstructure can generate the resonance effect of magnetic dipole among coupled layers, leading to the characteristics of broadband absorption.

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“…These PLAs can also be realized in planar semiconductor based metasurfaces and they can go beyond the Yablonovitch limit [15]- [21]. These metal-semiconductor (MS) designs could be of particular interest in the vast variety of optoelectronic applications.…”

mentioning

confidence: 99%

Spectrally Selective Ultrathin Photodetectors Using Strong Interference in Nanocavity Design

Ghobadi

Demirağ

Hajian

et al. 2019

IEEE Electron Device Lett.

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Thinning the active layer's thickness of the semiconductor down to a level comparable with the carriers' diffusion length while keeping its absorption high is an ultimate goal to boost the performance of optoelectronic devices. Strong interference in multilayer structures is one of the promising and practical solutions owing to their simple and large-scale compatible fabrication route. These nanocavity designs not only provide near unity absorption, but they can also be designed in a way that a spectrally selective absorption response can be achieved. In this letter, we will demonstrate the functionality of a metalinsulator-semiconductor (MIS) cavity to obtain spectrally selective ultrathin photodetectors. To prove our theoretical and numerical findings, a 4-nm-thick amorphous silicon (a-Si)-based MIS cavity is designed, fabricated, and characterized. The experimental results show that the optimized cavity design can act as an efficient visible blind ultraviolet (UV) photodetector. The proposed design shows the responsivity values of 120 and 2.5 mA/W in the UV (λ = 350 nm) and visible (λ = 500 nm) regions, respectively.

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Semiconductor meta-surface based perfect light absorber

Cited by 35 publications

References 46 publications

Semiconductor Thin Film Based Metasurfaces and Metamaterials for Photovoltaic and Photoelectrochemical Water Splitting Applications

Semiconductor Thin Film Based Metasurfaces and Metamaterials for Photovoltaic and Photoelectrochemical Water Splitting Applications

Polarization‐independent multiband metamaterials absorber by fundamental cavity mode of multilayer microstructure

Spectrally Selective Ultrathin Photodetectors Using Strong Interference in Nanocavity Design

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