scholarly journals Fast Response GaAs Photodetector Based on Constructing Electron Transmission Channel

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1160
Author(s):  
Shuai Guo ◽  
Xue Chen ◽  
Dengkui Wang ◽  
Xuan Fang ◽  
Dan Fang ◽  
...  
Keyword(s):  
High Speed ◽  
Surface States ◽  
Response Speed ◽  
Fast Response ◽  
Transmission Channel ◽  
Electron Transmission ◽  
Speed Performance ◽  
Gaas Nanowire ◽  
Low Dimensional ◽  
Low Dimensional Materials

Low-dimensional GaAs photodetectors have drawn a great deal of attention because of their unique absorption properties and superior responsivity. However, their slow response speed caused by surface states presents challenges. In this paper, a mixed-dimensional GaAs photodetector is fabricated utilizing a single GaAs nanowire (NW) and a GaAs 2D non-layer sheet (2DNLS). The photodetector exhibits a fast response with a rise time of ~4.7 ms and decay time of ~6.1 ms. The high-speed performance is attributed to an electron transmission channel at the interface between the GaAs NW and GaAs 2DNLS. Furthermore, the fast electron channel is confirmed by eliminating interface states via wet passivation. This work puts forward an effective way to realize a high-speed photodetector by utilizing the surface states of low-dimensional materials.

Enhanced UV Photon-response of Tin Nano Cluster Loaded- laser Irradiated ZnO Thin film detector

2011 ◽  
Vol 1288 ◽  
Author(s):  
Rashmi Menon ◽  
K. Sreenivas ◽  
Vinay Gupta
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetron Sputtering ◽  
Surface States ◽  
Response Speed ◽  
Rf Magnetron Sputtering ◽  
Fast Response ◽  
Zno Thin Films ◽  
Zno Thin Film ◽  
Photo Response

ABSTRACTZinc Oxide (ZnO), II-VI compound semiconductor, is a promising material for ultraviolet (UV) photon sensor applications due to its attractive properties such as good photoconductivity, ease processing at low temperatures and excellent radiation hardness. The rf magnetron sputtering is a suitable deposition technique due to better control over stoichiometry and deposition of uniform film. Studies have shown that the presence of surface defects in ZnO and subsequently their passivation are crucial for enhanced photo-response characteristics, and to obtain the fast response speed. Worldwide efforts are continuing to develop good quality ZnO thin films with novel design structures for realization of an efficient UV photon sensor. In the present work, UV photon sensor is fabricated using a ZnO thin films deposited by rf magnetron sputtering on the corning glass substrate. Photo-response, (Ion/Ioff) of as-grown ZnO film of thickness 100 nm is found to be 3×103 with response time of 90 ms for UV intensity of 140 μW/cm2 (λ = 365 nm). With irradiation on ZnO thin film by pulsed Nd:YAG laser (forth harmonics 266 nm), the sensitivity of the UV sensor is found to enhance. The photo-response increases after laser irradiation to 4x104 with a fast response speed of 35 ms and attributed to the change in surface states and the native defects in the ZnO thin film. Further, enhancement in the ultraviolet (UV) photo-response (8×104) of detector was observed after integrating the nano-scale islands of Sn metal on the surface of laser irradiated ZnO thin film.

Study of the Squeeze Film Damper of Larger Flow Rate High-Speed On/Off Valve

2011 ◽  
Vol 130-134 ◽  
pp. 594-598
Author(s):  
Hai Bing Jiang ◽  
Jian Ruan ◽  
Ming Ming Wu ◽  
Tao Wang
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Response Speed ◽  
Fast Response ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Perfect Performance ◽  
Sealing Performance ◽  
New Type ◽  
Off Time

A new type of squeeze film damper (SFD) is designed to reduce spool’s impact and vibration which happen in the two-stage larger flow rate high-speed on/off valve with the 450 L/min flow rate and 8ms turn-off time, the valve’s sealing performance、reliability and service life improve largely, and the valve’s response speed doesn’t drop. The simulated and experimental results show: The damper has optimum buffering performance when oil film thickness is 0.1mm, and the spool closing process approach ideal state. The valve will has a great potential application in the powerful occasions because of it's perfect performance: larger flow rate、fast response and novel damper.

scholarly journals Observing Structural Dynamics and Measuring Chemical Kinetics in Low Dimensional Materials Using High Speed Imaging

2019 ◽  
Vol 25 (S2) ◽  
pp. 1682-1683
Author(s):  
A I Kirkland ◽  
C. S. Allen ◽  
E. Besley ◽  
C. Huang ◽  
J. Kim ◽  
...  
Keyword(s):  
Chemical Kinetics ◽  
Structural Dynamics ◽  
High Speed ◽  
High Speed Imaging ◽  
Low Dimensional ◽  
Low Dimensional Materials

Photoresponse improvement of mixed-dimensional 1D–2D GaAs photodetectors by incorporating constructive interface states

Nanoscale ◽  
2021 ◽  
Author(s):  
Dengkui Wang ◽  
Xue Chen ◽  
Xuan Fang ◽  
Jilong Tang ◽  
Fengyuan Lin ◽  
...  
Keyword(s):  
Surface States ◽  
Interface States ◽  
Low Dimensional ◽  
Low Dimensional Materials

A mixed-dimensional photodetector was constructed to convert the harmful surface states of low-dimensional materials into their constructive interface states.

scholarly journals Recent Advances in High Speed Photodetectors for eSWIR/MWIR/LWIR Applications

Photonics ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 14
Author(s):  
Baile Chen ◽  
Yaojiang Chen ◽  
Zhuo Deng
Keyword(s):  
Short Wavelength ◽  
High Speed ◽  
State Of The Art ◽  
Response Speed ◽  
Optical Fiber Communication ◽  
Fiber Communication ◽  
Long Wavelength ◽  
Speed Performance ◽  
Response Performance ◽  
Long Wavelength Infrared

High speed photodetectors operating at a telecommunication band (from 1260 to 1625 nm) have been well studied with the development of an optical fiber communication system. Recent innovations of photonic systems have raised new requirements on the bandwidth of photodetectors with cutoff wavelengths from extended short wavelength infrared (eSWIR) to long wavelength infrared (LWIR). However, the frequency response performance of photodetectors in these longer wavelength bands is less studied, and the performances of the current high-speed photodetectors in these bands are still not comparable with those in the telecommunication band. In this paper, technical routes to achieve high response speed performance of photodetectors in the extended short wavelength infrared/mid wavelength infrared/long wavelength infrared (eSWIR/MWIR/LWIR) band are discussed, and the state-of-the-art performances are reviewed.

scholarly journals Research Progress on Terahertz Quantum-Well Photodetector and Its Application

2021 ◽  
Vol 9 ◽  
Author(s):  
Dixiang Shao ◽  
Zhanglong Fu ◽  
Zhiyong Tan ◽  
Chang Wang ◽  
Fucheng Qiu ◽  
...  
Keyword(s):  
Quantum Well ◽  
High Speed ◽  
Theoretical Calculations ◽  
Material Design ◽  
Response Speed ◽  
Peak Frequency ◽  
Fast Response ◽  
Detection Sensitivity ◽  
Research Progress ◽  
Frequency Error

Compared with other typical terahertz (THz) detectors, the quantum-well photodetector (QWP) has the advantages of high detection sensitivity, fast response, mature fabrication, small size, and easy integration. Therefore, it is suitable for high-speed detection and imaging applications at the THz band. Researchers, both domestic and overseas, have systematically studied material design and device performance of the THz QWP. The design of the device is such that the peak frequency error is within 8%, the maximum peak responsibility is 5.5 A/W, the fastest response speed is 6.2 GHz, the best noise equivalent power is ∼10−13 W/Hz0.5, and the spectrum range is 2.5–6.5 THz. In this article, firstly the basic principles and theoretical calculations of the THz QWP are described, and then the research progress of the THz QWP in our research group at imaging and communication is reviewed, which looks forward to its future development.

Direct Current Deadbeat Predictive Controller for BLDC Motor Using Single DC-Link Current Sensor

2020 ◽  
Vol 38 (8A) ◽  
pp. 1187-1199
Author(s):  
Qaed M. Ali ◽  
Mohammed M. Ezzalden
Keyword(s):  
Control System ◽  
High Speed ◽  
Fast Response ◽  
Bldc Motor ◽  
Current Controller ◽  
Three Phase ◽  
Predictive Controller ◽  
Two Phases ◽  
Dc Current ◽  
Three Phase Inverter

BLDC motors are characterized by electronic commutation, which is performed by using an electric three-phase inverter. The direct control system of the BLDC motor consists of double loops; including the inner-loop for current regulating and outer-loop for speed control. The operation of the current controller requires feedback of motor currents; the conventional current controller uses two current sensors on the ac side of the inverter to measure the currents of two phases, while the third current would be accordingly calculated. These two sensors should have the same characteristics, to achieve balanced current measurements. It should be noted that the sensitivity of these sensors changes with time. In the case of one sensor fails, both of them must be replaced. To overcome this problem, it is preferable to use one sensor instead of two. The proposed control system is based on a deadbeat predictive controller, which is used to regulate the DC current of the BLDC motor. Such a controller can be considered as digital controller mode, which has fast response, high precision and can be easily implemented with microprocessor. The proposed control system has been simulated using Matlab software, and the system is tested at a different operating condition such as low speed and high speed.

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