The enhanced terahertz absorption of metal gratings/Si-based blocked-impurity-band (BIB) hybrid structures

Tong, Wulin; Chen, Yulu; Wang, Lin; Wang, Bingbing; Guo, Wanlong; Liu, Wenhui; Chen, Dong; Hu, Yijia; Wang, Xiaodong

doi:10.1007/s11082-021-03229-8

Cited by 2 publications

(3 citation statements)

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“…The experimental results in Figure 2 c demonstrate the same tendency, whereby the peak position changes from 21.71 to 24.50 to 36.59 μm with the increasing grating period. According to the Drude theory [ 14 , 16 , 17 ], the plasmon resonance frequency of metal gratings,

, can be calculated by the formula:

where

is the effective electron density,

is the electron charge,

is the vacuum dielectric constant, and

is the electron effective mass. Thus, the relationship between the resonance wavelength,

, and the parameters of metal grating,

and

, can easily be deduced as follows:

…”

Section: Resultsmentioning

confidence: 99%

“…The 500 μm-thick Si substrate was thinned to 130 μm using a horizontal rotary grinding machine (HRG-150) followed by chemical mechanical polishing (AP-380F), and then divided into three pieces. Considering the response spectrum of the bare Si-based BIB detector and manufacturing limitations of small-period metal grating [ 14 , 15 ], the metal gratings with different periods of 16, 20, and 32 μm and a duty ratio of 3/4 were deposited on the pieces by photolithography and electron beam evaporation with Ti (100 nm)/Al (4900 nm) materials, respectively. Al is selected for metal grating because of its mature preparation process and good compatibility with the devices used.…”

Section: Methodsmentioning

confidence: 99%

“…Yakimov et al indicated that the photoresponse intensity of the quantum dot mid-infrared photodetector can be enhanced about 15 times at a wavelength of 4.4 μm by covering an Au layer with two-dimensional subwavelength hole arrays, and that enhanced sensitivity arises from coupling the surface plasmon resonance and diffractive effect [ 13 ]. Based on this, a metal grating/Si-based BIB hybrid structure was designed and theoretically simulated in our previous work [ 14 ]. It was demonstrated that the absorption peak wavelength of the hybrid structure could be modulated from 24.46 to 36.53 μm by changing the metal grating periods from 8 to 32 μm.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wavelength Modulation Characteristics of Metal Gratings on Si-Based Blocked-Impurity-Band (BIB) Terahertz Detectors

Chen¹,

Dong²,

Zhou³

et al. 2022

Micromachines

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In this work, the wavelength selection characteristics of metal gratings on Si-based blocked-impurity-band (BIB) detectors in the terahertz band were studied by performing experiments and a finite difference time domain (FDTD) simulation. The transmission spectra of metal gratings with different periods on 130 μm intrinsic Si substrates were measured. When the metal grating period increased from 16 to 20 to 32 μm, the peak position of the spectrum moved from 21.71 to 24.50 to 36.59 μm, which is in good agreement with the FDTD simulation results. The structure with the period of 32 μm shows the best wavelength selective transmission characteristics. Then, the bare Si-based BIB devices and metal grating/Si-based BIB hybrid devices with different thicknesses of blocking layers of 2 and 5 μm were fabricated. By covering different periods of metal gratings for the devices with a thicker blocking layer of 2 μm, we obtained more effective wavelength selection characteristics and stronger response spectra enhancement ratios that were about 1.3, 2.4, or 1.9 times. This was mainly due to the localized optical field enhancement effect of the plasmons resonance in metal gratings, which decays exponentially in a vertical direction. Our results demonstrate a new approach for the Si-based BIB detector to realize multiband selective detection applications.

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, can be calculated by the formula:

where

is the effective electron density,

is the electron charge,

is the vacuum dielectric constant, and

is the electron effective mass. Thus, the relationship between the resonance wavelength,

, and the parameters of metal grating,

and

, can easily be deduced as follows:

…”

Section: Resultsmentioning