Abstract:Broadband light perfect absorbers (BPAs) are desirable for applications in numerous optoelectronics devices. In this work, a semiconductor-based broadband light perfect absorber (S-BPA) has been numerically demonstrated by utilizing plasmonlike resonances of high-index semiconductor resonators. A maximal absorption of 99.7% is observed in the near-infrared region. By taking the absorption above 80% into account, the spectral bandwidth reaches 340 nm. The absorption properties mainly originate from the optical … Show more
“…2 that the absorbed light is mainly dissipated in graphene rather than in Ag. Moreover, the total absorption at the third peak exceeds 98.5%, very similar to much reported metamaterial electromagnetic wave perfect absorbers [ 69 – 75 ], which have many potential applications such as solar cells [ 76 – 81 ]. Fig.…”
It is well known that a suspended monolayer graphene has a weak light absorption efficiency of about 2.3% at normal incidence, which is disadvantageous to some applications in optoelectronic devices. In this work, we will numerically study multiband and broadband absorption enhancement of monolayer graphene over the whole visible spectrum, due to multiple magnetic dipole resonances in metamaterials. The unit cell of the metamaterials is composed of a graphene monolayer sandwiched between four Ag nanodisks with different diameters and a SiO2 spacer on an Ag substrate. The near-field plasmon hybridizations between individual Ag nanodisks and the Ag substrate form four independent magnetic dipole modes, which result into multiband absorption enhancement of monolayer graphene at optical frequencies. When the resonance wavelengths of the magnetic dipole modes are tuned to approach one another by changing the diameters of the Ag nanodisks, a broadband absorption enhancement can be achieved. The position of the absorption band in monolayer graphene can be also controlled by varying the thickness of the SiO2 spacer or the distance between the Ag nanodisks. Our designed graphene light absorber may find some potential applications in optoelectronic devices, such as photodetectors.
“…2 that the absorbed light is mainly dissipated in graphene rather than in Ag. Moreover, the total absorption at the third peak exceeds 98.5%, very similar to much reported metamaterial electromagnetic wave perfect absorbers [ 69 – 75 ], which have many potential applications such as solar cells [ 76 – 81 ]. Fig.…”
It is well known that a suspended monolayer graphene has a weak light absorption efficiency of about 2.3% at normal incidence, which is disadvantageous to some applications in optoelectronic devices. In this work, we will numerically study multiband and broadband absorption enhancement of monolayer graphene over the whole visible spectrum, due to multiple magnetic dipole resonances in metamaterials. The unit cell of the metamaterials is composed of a graphene monolayer sandwiched between four Ag nanodisks with different diameters and a SiO2 spacer on an Ag substrate. The near-field plasmon hybridizations between individual Ag nanodisks and the Ag substrate form four independent magnetic dipole modes, which result into multiband absorption enhancement of monolayer graphene at optical frequencies. When the resonance wavelengths of the magnetic dipole modes are tuned to approach one another by changing the diameters of the Ag nanodisks, a broadband absorption enhancement can be achieved. The position of the absorption band in monolayer graphene can be also controlled by varying the thickness of the SiO2 spacer or the distance between the Ag nanodisks. Our designed graphene light absorber may find some potential applications in optoelectronic devices, such as photodetectors.
“…[27][28][29][30][31][32] So Liu et al reported a broadband semiconductor absorber composed of a GaAs cylinder resonator and an ultrathin GaAs film on an Al substrate. [33] It possessed an absorption band with bandwidth up to 340 nm in the near-infrared region. However, most of the researches on semiconductor-based metamaterial absorbers were carried out at THz or infrared wavelengths, and the research results of visible light absorbers designed with semiconductor materials are still less so far.…”
It is desirable to have electromagnetic wave absorbers with ultrathin structural thickness and broader spectral absorption bandwidth with numerous applications in optoelectronics. In this paper, we theoretically propose and numerically demonstrate a novel ultrathin nanostructure absorber composed of semiconductor nanoring array and a uniform gold substrate. The results show that the absorption covers the entire visible light region, achieving an average absorption rate more than 90% in a wavelength range from 300 nm to 740 nm and a nearly perfect absorption from 450 nm to 500 nm, and the polarization insensitivity performance is particularly great. The absorption performance is mainly caused by the electrical resonance and magnetic resonance of semiconductor nanoring array as well as the field coupling effects. Our designed broadband visible light absorber has wide application prospects in the fields of thermal photovoltaics and photodetectors.
“…Semiconductor materials have also drawn intensive interest due to their low cost and high conversion efficiency for solar energy as compared with the conventional thin-film devices [31][32][33][34][35][36][37][38][39]. Most of the solar absorbers are based on silicon (Si) due to its natural abundance and nearly ideal energy band gap [31,34].…”
Section: Introductionmentioning
confidence: 99%
“…However, the efficiency of solar cells is limited when the thickness of Si layers reduces. Therefore, light trapping has now become one of the major topics in the thin film solar cells [38]. Recently, gallium arsenide (GaAs) has become a good competitor because of its unique optical property and high conversion efficiency [36][37][38][39], which have been demonstrated experimentally in solar harvesting.…”
Section: Introductionmentioning
confidence: 99%
“…Therefore, light trapping has now become one of the major topics in the thin film solar cells [38]. Recently, gallium arsenide (GaAs) has become a good competitor because of its unique optical property and high conversion efficiency [36][37][38][39], which have been demonstrated experimentally in solar harvesting. For instance, Massiot et al presented the metal nanogrid for broadband multi-resonant light-harvesting in the ultrathin GaAs layers with the absorption bandwidth of 380 nm (from 450 to 830 nm) [40].…”
Light trapping is an important performance of ultra-thin solar cells because it cannot only increase the optical absorption in the photoactive region but it also allows for the efficient absorption with very little materials. Semiconductor-nanoantenna has the ability to enhance light trapping and raise the transfer efficiency of solar energy. In this work, we present a solar absorber based on the gallium arsenide (GaAs) nanoantennas. Near-perfect light absorption (above 90%) is achieved in the wavelength which ranges from 468 to 2870 nm, showing an ultrabroadband and near-unity light trapping for the sun's radiation. A high short-circuit current density up to 61.947 mA/cm 2 is obtained. Moreover, the solar absorber is with good structural stability and high temperature tolerance. These offer new perspectives for achieving ultra-compact efficient photovoltaic cells and thermal emitters.
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