Special issue-New infrared device
Research progress of infrared and terahertz detectors based on two-dimensional materials regulated by photo-hot carrier
2020, 49(1): 0103001. doi: 10.3788/IRLA202049.0103001
[Abstract](1429) [PDF 9363KB](229) [Cited by] ()
Due to myriad applications, infrared and terahertz are playing an important role in the fields of spectroscopy, imaging, wireless communication and remote sensing. However, be limited by the low photon energy in the infrared terahertz band, the detection encounters great difficulties, so it is a anenormous challenge to realize infrared and terahertz detection with high sensitivity, high speed and high stability. Two-dimensional materials offer new opportunities for infrared and terahertz detection due to their high mobility, adjustable band gap, and few surface dangling bonds. The development of two-dimensional material infrared and terahertz detectors regulated by photo-hot carrier is in the ascendant. This paper mainly introduced the latest research progress of infrared and terahertz detectors based on photo-hot carrier regulation. This article will expand on materials, device structures, response bands, and response mechanisms.
2020, 49(1): 0103002. doi: 10.3788/IRLA202049.0103002
[Abstract](952) [PDF 6119KB](172) [Cited by] ()
Antimony telluride (Sb2Te3) is a new type of two-dimensional layered material, in this paper, the "top-down" ultrasonic exfoliation method was used to prepare antimony telluride quantum dots (Sb2Te3 QDs) for the first time, with antimony telluride powder as raw material, and N-methyl pyrrolidone (NMP) as the dispersant. A variety of characterizations(SEM, TEM, AFM, XPS, XRD, etc.) for the structure and morphology of the prepared Sb2Te3 QDs were performed. The optical properties of Sb2Te3 QDs were studied using UV-Vis, PL and PLE. It is found that the average particle size of the prepared Sb2Te3 QDs is 2.3 nm, and the average height is 1.9 nm, with a good dispersive particle size uniformity, the PL and PLE peaks have a redshift, both PL and PLE are dependent on the excitation wavelength and emission wavelength. It is also found that Sb2Te3 QDs has obvious absorption and photoluminescence in the infrared band. The results indicate that the ultrasonic exfoliation method is feasible to prepare Sb2Te3 QDs, the characteristics of the material show the potential application in infrared detector.
2020, 49(1): 0103003. doi: 10.3788/IRLA202049.0103003
[Abstract](1494) [PDF 17361KB](219) [Cited by] ()
Graphene has some unique properties, such as ultra-high carrier mobility, zero band gap, broadband response, which make it a promising material in infrared photodetection. In this review, the development history of graphene-based infrared detectors was analyzed, and the mechanism of relevant photoelectric response was summarized. The responsivity, wave-band, response speed and device structure were sorted out. The challenges of material preparation and process compatibility of graphene-based detectors were also discussed and prospected.
2020, 49(1): 0103004. doi: 10.3788/IRLA202049.0103004
[Abstract](1031) [PDF 1711KB](150) [Cited by] ()
Germanium (Ge) is considered as one of the most promising materials for near infrared (NIR) photodetectors, due to its large absorption coefficient at NIR wavelengths, high carrier mobilities, and process compatibility with silicon (Si) architecture. Focusing on the challenges of Ge NIR photodetectors, in this paper, the progress of Ge materials and technologies for photodetectors in our group was reviewed extensively. Firstly, the preparation process of Si-based Ge materials was introduced, in which high crystal quality Si-based Ge materials were fabricated by a two-step epitaxy method, Ge/Si wafer bonding, and Ge condensation techniques, respectively. Then the n-type doping technology of Ge was studied, in which high n-type doping concentrations and shallow junctions of Ge materials were prepared by two-step annealing (low temperature pre-annealing and excimer laser annealing) for phosphorus-implanted Ge substrate and spin-on doping of phosphorus on Ge substrate, respectively. Finally, the modulation of Schottky barrier height of metal/Ge contacts were studied, and a high-performance Ge Schottky photodetector was prepared by combining ITO transparent electrode and ultra-thin metal film interlayer.
2020, 49(1): 0103005. doi: 10.3788/IRLA202049.0103005
[Abstract](1219) [PDF 3722KB](130) [Cited by] ()
The avalanche photodiode detector based on InGaAs/InP has a working response band range of 0.9-1.67 μm, which has high detection efficiency and single photonic sensitivity in Geiger mode. By configuring different bias circuits, it can work in gating and free running mode. At present, the gating mode is mainly used, and can be applied to quantum key distribution with known arrival time of photons. In laser ranging, lidar imaging and other applications, when the arrival time of photons is unknown, the device needs to work in free running mode. Through internal integration or on-chip integration of self-quenching devices, the detector itself has the function of self-quenching or self-recovery, does not need external quenching circuit, and can work in free running mode. This greatly expands the application field of InGaAs/InP single-photonic detector, and has the advantage of fabricating single-photonic detector array at the same time. In addition, the cutoff wavelength of the detector can be further extended to 2.4 μm by using InGaAs/GaAsSb II superlattice material as the absorption layer of the avalanche photodiode. In this paper, the Geiger mode APD was introduced, and the principle and performance of the current free running mode and the extended wavelength inp based single photonic detector were described in detail.
2020, 49(1): 0103006. doi: 10.3788/IRLA202049.0103006
[Abstract](1588) [PDF 3214KB](293) [Cited by] ()
SWIR InGaAs FPAs are widely applied to space remote sensing, low light level night vision and medical diagnostics due to the high detectivity and uniformity. Highly sensitive NIR InGaAs FPAs with response covering from 0.9 μm to 1.7 μm, the extended SWIR InGaAs FPAs with the cutoff wavelengths from 1.0 μm to 2.5 μm, and other novel SWIR InGaAs FPAs have been studied respectively at Shanghai Institute of Technical Physics of Chinese Academy of Sciences over the past ten years. NIR InGaAs FPAs have developed from some typical linear 256×1, 512×1 FPAs to 2D format 320×256, 640×512, 4 000×128 and 1 280×1 024 FPAs. Typically, the dark current density was about 5 nA/cm2 and the peak detectivity was superior to 5×1012 cm·Hz1/2/W at room temperature. 2D format 1 024×256, 1 024×512 extended wavelength InGaAs FPAs with high frame rate were also developed for the hyperspectral applications at SITP. The dark current density drops to 10 nA/cm2 and peak detectivity was over 5×1012 cm·Hz1/2/W at 200 K. By using novel epitaxial materials and the light trapping structures, the visible-NIR InGaAs FPAs for wavelength band of 0.4-1.7 μm have also been developed. The as-prepared 320×256, 640×512 InGaAs FPAs were obtained with quantum efficiency superior to email@example.com m, firstname.lastname@example.org m and email@example.com m. For polarimetric detecting, InGaAs devices integrated with sub-wavelength metal grating of different angles (0°, 45°, 90°, 135°) have been developed, which exhibit the extinction ratio of greater than 20:1.
2020, 49(1): 0103007. doi: 10.3788/IRLA202049.0103007
[Abstract](1116) [PDF 1560KB](93) [Cited by] ()
New infrared devices prepared by InAs/GaSb superlattice materials have developed rapidly in the last decade. The paper carries out practical researches on mid-/short-wavelength dual-color infrared detector based on type-II InAs/GaSb superlattice. Firstly, a mid-/short-wavelength dual-color chip structure was designed based on two back-to-back n-i-p junctions. Then the PNP superlattice material with complete structure, smooth surface and low defect density was grown by molecular beam epitaxy. Finally, 320×256 focal plane arrays with excellent performance was fabricated and measured. The RA value of middle-wave channel reached 26 kΩ·cm2 and the short-wave channel reached 562 kΩ·cm2 at 77 K. The spectral response indicated the short-wave response band of 1.7-3 μm and the middle-wave of 3-5 μm. The middle-wave channel exhibits a detectivity value of 3.12×1011 cm·Hz1/2W-1, a photo-response non-uniformity of 9.9% and an effective pixel rate of 98.46%, while the short-wave channel exhibits a detectivity value of 1.34×1011 cm·Hz1/2W-1, a photo-response non-uniformity of 9.7% and an effective pixel rate of 98.06%.
2020, 49(1): 0103008. doi: 10.3788/IRLA202049.0103008
[Abstract](965) [PDF 4471KB](115) [Cited by] ()
640×512 Quantum Well Infrared Photo-detector(QWIP) long wavelength infrared(LWIR) focal plane arrays(FPA) were made by using GaAs/AlGaAs quantum well structure. The response spectra were at 10.55 μm. Integrated with rotation sterling cooler which gave a temperature of 50 K, the FPA was measured to find the results that NETD was about 22.5 mK. The FPA assembly kept good performance after the switch-on-off cycling test and thermal vacuum test. The illumination non-uniformity of the focal plane with a cold shield was calculated with a numerical method. The results were compared with the approximate analytic method. It is shown that numerical method should be used for small F-numbers. Thus, the measured non-uniformity is believed to be dominated by the illumination non-uniformity. By using the MEEP FDTD software, calculation about the near-field photo-coupled electrical-field energy were designed and results show that current QWIP structure parameters are near optimized in term of optical diffraction.
2020, 49(1): 0103009. doi: 10.3788/IRLA202049.0103009
[Abstract](1153) [PDF 4798KB](165) [Cited by] ()
It's the trend of information technology development that infrared focal plane array (FPA) outputs digital signal directly, the critical technique is the digital readout integrated circuit (ROIC). The architecture of digital ROIC was introduced in this paper after the summary of related research status. The sources and influence of temporal noise and spatial noise were analyzed in detail, then the design guide for low noise was also shown. In addition, two digital ROICs were designed based on the discussion of linearity, dynamic range and frame rate. The first ROIC was implemented with column-level ADCs, which was used for 640×512 digital FPA. The measurement results show that the readout noise of ROIC is 150 μV, and the NETD with mid-wave infrared detectors is 13 mK. Digital pixel architecture is used for the second ROIC, which is connected to 384×288 long-wave infrared FPA. The measured NETD is less than 4 mK, and the dynamic range is larger than 90 dB. The max frame rate achieves 1 000 Hz. The two ROIC prototypes effectively improve the sensitivity, dynamic range and frame rate of infrared FPA, which confirms the advantages of digital ROIC technology to the performance development of infrared detectors.
2020, 49(1): 0103010. doi: 10.3788/IRLA202049.0103010
[Abstract](1284) [PDF 7207KB](245) [Cited by] ()
The applications of the second HgCdTe Infrared Focal Plane Arrays(IRFPA) have exploded in the past 10 years, meanwhile the third IRFPA has developed rapidly. This article makes a brief retrospect in development of HgCdTe IRFPA detector, combines with applications of HgCdTe IRFPA detector, summarizes the research works and the engineering applications of HgCdTe IRFPA detector and looks forward to the further development of HgCdTe IRFPA detector.
2020, 49(1): 0103011. doi: 10.3788/IRLA202049.0103011
[Abstract](1213) [PDF 1673KB](197) [Cited by] ()
The key to realize very high sensitivity infrared detector is to obtain as much charge storage capacity as possible in the limited pixel area of readout circuit. The pixel-level ADC based on pulse frequency modulation is the main method to realize the readout circuit of very sensitive infrared detector. The principle of pixel-level pulse frequency modulation ADC was described. The progress of pixel-level digital readout circuit in MIT Lincoln Laboratory of the USA and CEA-LETI of France were introduced. As a new technology of expanding circuit density from three-dimensional space, the progress of 3D readout circuit was introduced. Finally, the development of readout circuit for very high sensitivity infrared detector in Kunming Institute of Physics was introduced. Using pixel-level ADC technology and digital domain TDI technology, the long-wave 512×8 digital TDI infrared detector assembly was developed by Kunming Institute of Physics with the peak sensitivity of 1.5 mK.