This paper is a study composed of experiment and simulation. We conceived a blocked-impurity-band hybrid structure for terahertz radiation detection. The modulation effect of sub-wavelength metal grating on light absorption has been analyzed theoretically. The optical absorption and spectral response of sub-wavelength metal grating/Si:P blocked-impurity-band hybrid structure detectors are simulated by Finite Difference-Time Domain solution. Compared with the detector without grating structure, the hybrid structure detectors have the effects of selective absorption amplification and filtering. Moreover, the fabrication and experimental details of the hybrid structure detectors have been investigated. The results show that the response peak wavelength 18.3 μm of the Si:P blocked-impurity-band detector has been modulated to 14.3, 22.8, 28.2, and 33.1 μm (∼9.1 THz). Especially, about 140% absorption enhancement is achieved at the response peak wavelength 28.2 μm. Furthermore, the modulation mechanisms of spectral responses on operation bias voltages and temperatures have also been studied. This study provided an effective method to modulate the spectral response of the Si:P BIB detector.

An anti-reflection coating on a back-illuminated 128 × 128 array Si-based blocked impurity band (BIB) detector in a very-long-wave infrared range was designed in this work. The reflectance and transmittance spectra of ZnS films with different thicknesses on intrinsic Si substrates were studied with a FDTD simulation and experiment. Compared to bare Si substrate, the reflectance of Si coated with 1.5, 2.0, 2.5, and 3.0 μm thick ZnS significantly decreased, while the transmittance increased in the range of 10.0~25.0 μm band. The transmittance enhancement ratio reached approximately 32%, 32%, 28%, and 29%, respectively. It was evidenced that the enhanced transmission at a specific wavelength was caused by the effective interference cancellation effect. Then, a 2.0 μm thick ZnS thin film was deposited on the backside of the 128 × 128 array Si-based BIB detector. The spectral responsivity of the detector increased significantly. Additionally, the blackbody responsivity increased by approximately 36%, suggesting that the ZnS film is an ideal anti-reflection material for VLWIR detectors in the range of 10.0~25.0 μm band.

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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Formamidine lead iodide (FAPbI3) is an important material for realizing high‐performance near‐infrared light‐emitting diodes (NIR‐LEDs). However, due to the uncontrollable growth of solution‐processed films which usually causes low coverage, and poor surface morphology, the development of FAPbI3‐based NIR‐LEDs is hindered, restraining its potential industrial applications. In this work, by employing glutamine (Gln) in perovskite precursor, the quality of FAPbI3 film is improved significantly. Due to the ameliorated solution process by the organic additive, the film coverage over the substrate is substantially enhanced. Meanwhile, the trap state of grain is largely reduced. Consequently, NIR perovskite LEDs are demonstrated with a maximum external quantum efficiency (EQE) of 15% with the emission peak at 795 nm, which is four times higher than the device with pristine perovskite film.