14 results about "Dark count rate" patented technology

The invention relates to the technical field of photoelectric detection, and provides a single-photon counter circuit for weak light detection based on a photomultiplier, and the single-photon counter comprises a photoelectric conversion circuit, a differential amplification circuit, a threshold comparison circuit and a signal shaping circuit. The photoelectric conversion circuit is composed of a photomultiplier, a high-voltage power supply circuit and a voltage division circuit, detects weak light signals and outputs two paths of current signals through photoelectric conversion. The differential amplification circuit carries out differential amplification on the two current signals through a differential amplifier. The threshold comparison circuit compares two input signals, filters out signals with the amplitude lower than 1 / 2 of a set threshold, and outputs a single-path effective signal. And the signal shaping circuit shapes the effective signal and finally outputs the effective signal in a TTL pulse mode. According to the single photon counter circuit for weak light detection, the background dark counting rate is low, the sensitivity is high, and the counting unit module specially used for digital pulse statistics is connected behind the single photon counter circuit for counting single photons.

The application provides an optoelectronic device and a preparation method thereof, and an optoelectronic detection device, which can reduce the dark count rate of the device. The optoelectronic device comprises a substrate, a working area in the substrate, the working area comprising a first well region of a first conductivity type, a second well region and a first high-doped region, and a third well region, a fourth well region and a second high-doped region having a second conductivity type, wherein the third well region forms an avalanche region with at least one of the second well region and the first high-doped region, and the first well region is exposed to a first surface, and the first well region is configured to have the effect of a passivation layer to reduce the surface electric field of the first surface.

This invention discloses a superlattice multiplication layer avalanche diode and its fabrication method. The single-photon avalanche diode includes a graphene transparent electrode and, from bottom to top, an InP substrate, an n-type buffer layer, a superlattice absorption region, a p-type charge layer, a superlattice gradient region, a superlattice multiplication region, a p-type contact layer with a p-type contact window, and a passivation layer. The graphene transparent electrode is grown on the passivation layer and the p-type contact window, forming an ohmic contact with the p-type contact region. Magnetic metal nanoparticles that generate a local magnetic field are embedded in the superlattice multiplication region. The magnetic metal nanoparticles are uniformly distributed in-plane within a depth range of 5-400 nm from the interface in the light-gathering direction of the superlattice multiplication region. This invention combines the internal bandgap optimization of the superlattice with the external limiting pump capability of graphene to produce a synergistic effect, providing a single-photon avalanche diode with low dark count rate, weak afterpulse effect, high detection efficiency, and the ability to operate at relatively high temperatures.

The invention discloses a low-noise near-infrared single-photon avalanche detector and a preparation method thereof, the low-noise near-infrared single-photon avalanche detector comprises an n-type InP substrate, and an InP buffer layer, a GaAs < 0.51 > Sb < 0.49 > absorption layer, an In Ga < 1-a > As Sb < 1-b > energy band gradient layer, a composite charge layer containing an indium quantum dot array, an InP avalanche layer and an i-InP diffusion layer which grow on the front surface of the n-type InP substrate from bottom to top in sequence, the composite charge layer containing the indium quantum dot array comprises an InP gradient charge layer, an In quantum dot deposition layer and an InP constant charge thin layer which are sequentially grown from bottom to top. On the premise of keeping high photon detection efficiency of the detector, the dark counting rate and the post-pulse probability of the detector can be effectively reduced, and the performance and the reliability of the detector are remarkably improved.

This invention discloses a cerium-doped InP-based single-photon avalanche detector for space communication and its fabrication method. The detector's epitaxial structure, from bottom to top, includes a substrate, an N-type buffer layer, an absorption layer, a band transition layer, an N-type charge layer, an intrinsic multiplication layer, an intrinsic InP layer, and a cerium-doped P-type contact layer. The core innovation lies in the dual radiation-resistant design of the Ce-doped P-type contact layer and the Ce-doped modified stacked passivation film. The fabrication method involves MOCVD epitaxial growth, spin-coating source diffusion to prepare the P-type contact layer, ICP etching and wet repair, magnetron sputtering doping, and electrode fabrication. This invention utilizes Ce's unique electronic structure to suppress radiation-induced defects and combines this with an SACM structure to optimize the electric field distribution, achieving low dark count rate, high detection sensitivity, and excellent neutron radiation resistance. The process is compatible with existing semiconductor production lines and is suitable for wafer-level mass production, meeting the high-reliability single-photon detection requirements of aerospace missions such as space laser communication and quantum key distribution.

Embodiments of the present disclosure relate to dark count rate mitigation on avalanche photodiode based ambient light sensors. An example apparatus, a computer-implemented method, and an electronic device including an ambient light sensor configured to mitigate effects of a dark count rate associated with an avalanche photodiode are provided. The example apparatus includes an exposed avalanche photodiode array, a dark avalanche photodiode array, and a controller. The exposed avalanche photodiode array is positioned to receive ambient light from an external environment. The dark avalanche photodiode array is shielded by ambient light. The controller is configured to receive an exposure illuminometer corresponding to ambient light received at the exposed avalanche photodiode array. The controller is further configured to receive a dark illuminometer number corresponding to a dark count at the dark avalanche photodiode array. The controller determines an ambient light value based on a difference between the exposure illuminometer number and the darkness illuminometer number.

As described herein, the dark count rate (DCR) of perovskite photon-counting detectors (PCDs) was dominated by charge de-trapping from shallow traps located at the grain boundaries and surface, and the ultra-low DCR was achieved by suppressing the shallow traps by enhancing grain size and passivating film surface with diphenyl sulfide. The suppression of shallow traps made the perovskite PCDs have 100-1000 times lower DCR and much better response linearity to weak light than SiPMs. and the DCR was not sensitive to temperature due to small activation energy of charge traps. The zero-bias operating perovskite PCDs were demonstrated as γ-ray spectrum detectors with better energy resolution under 57Co source than commercial SiPMs at room temperature. At higher temperature up to 85° C. the perovskite PCDs are much superior to SiPMs by maintaining the energy resolution, showing their potential of working in harsh environment. This study discovered regular surface passivation also dramatically impact shallow charge traps, which should have implication of perovskite stability and doping.

The invention discloses a control method and system for stabilizing SiPM photoelectric performance through dynamic temperature control, and a temperature control method taking SiPM photoelectric performance stability as an ultimate target improves the design target of the temperature control system from stable temperature to stable dark count rate, and through the stable temperature as an intermediate variable, the design target of the temperature control system is improved to stable dark count rate. The final purpose of improving the terminal performance of the radiation detection system is directly served; the environment temperature change rate is introduced as a feedforward control coefficient to be complementary with PID feedback, predictive control over the SiPM core temperature is achieved, and the response speed and control quality of the system for resisting environment sudden change are remarkably improved. According to the method, dew point calculation and safety boundary depth are embedded, so that anti-condensation is converted from an independent rear protection function to an active predictive constraint condition in a control method, and high unification of safety and efficiency is realized; the method is suitable for improving dark counting rate stability and energy resolution of SiPM in a nuclear radiation detector in a complex environment.

The embodiment of the invention discloses a photoelectric conversion device, a forming method and an image sensor. The photoelectric conversion device includes: a substrate; a front trench isolation structure; at least two avalanche diode units formed on the substrate; each avalanche diode unit comprises a device region and a back side deep trench isolation structure surrounding the device region; the doped region is formed by outward diffusion from the front side trench isolation structure; the doped region has a doping concentration gradient which is gradually reduced outwards from the front side trench isolation structure; wherein at least one front side trench isolation structure exists between any two adjacent avalanche diode units; at least a portion of the doped region extends across the backside deep trench isolation structure, forming a dark current suppression region within each of two adjacent avalanche diode cells. By means of the mode, the dark count rate of the device can be reduced, and the device has better electrical performance and reliability.

The invention discloses a time delay estimation and distance measurement precision optimization method for entangled light coincidence measurement. According to the method, on the basis of a Poisson statistical model of coincidence counting, coincidence counting of delay sampling points is regarded as mutually independent observation, real time delay between signal photons and idle photons is used as a parameter to be estimated, a joint probability model and a log-likelihood function are constructed, Fisher information amount and a Cramer-Rao lower bound (CRLB) corresponding to the Fisher information amount are deduced, and the estimation accuracy of the Cramer-Rao lower bound (CRLB) is improved. The method is used for depicting the lower limit of variance which any unbiased estimator can reach under the observation model. In mean modeling, coincidence counting expectation is decomposed into signal coincidence and accidental coincidence, and a Gaussian second-order correlation function is adopted to describe a coincidence counting peak, so that CRLB can explicitly reflect the effect of physical and statistical parameters of a system on precision limit. On the basis, sensitivity analysis is performed on key parameters such as acquisition duration, two-channel single photon counting rate, dark counting rate, coincidence gate width, delay scanning step length and the like, a quantitative influence relationship of the key parameters on Fisher information and CRLB is given, and the coincidence gate width shows a single-peak trend of decreasing firstly and then increasing for a precision lower bound; therefore, there is a realizable optimal gate width to minimize CRLB. And finally, mapping the time delay estimation uncertainty into distance precision according to a distance measurement model, and forming a parameter configuration closed loop under the constraint of a set acquisition duration and a noise budget. Compared with a scheme of setting a door width depending on experience and repeated trial and error, the method provides an explainable and reproducible lower bound driving parameter selection criterion, and engineering parameter design and performance optimization of quantum distance measurement and related positioning and imaging systems can be directly supported.

The present application relates to the technical field of single photon detection, and particularly relates to a single photon detector performance parameter measurement method, device and equipment and a storage medium, the method constructs a statistical histogram of time domain interval data, establishes statistical distribution characteristics of a photon counting rate and dark counting of a single photon detector, and defines a probability of no photon detection event within a light pulse duration and an ideal probability of no dark pulse within a preset time window based on the statistical distribution characteristics, then calculates a probability of a single photon signal generated by a periodic light pulse based on the above obtained parameters, and finally determines a periodic statistical peak value based on the statistical histogram and the probability of the single photon signal generated by the periodic light pulse, and calculates an average detected photon number and a dark counting rate, thereby obtaining a dead time, achieving simultaneous representation of average detected photon number, dark counting rate and dead time and other information of a single photon detector through one-time data acquisition, and solving the problems of large data storage and high cost in the traditional method.

The invention provides a photoelectric device, a preparation method thereof and a photoelectric detection device. The dark count rate of the device can be reduced. The photoelectric device includes: a substrate; a working region in the substrate, the working region including a first well region, a second well region and a first highly doped region of the first conductivity type, and a third well region, a fourth well region and a second highly doped region of the second conductivity type, where the third well region forms an avalanche region with at least one of the second well region and the first highly doped region, and the fourth well region forms an avalanche region with at least one of the second well region and the first highly doped region. The first well region is exposed out of the first surface, and the first well region is configured to have the effect of a passivation layer so as to reduce the surface electric field of the first surface.

An example apparatus, computer-implemented method, and electronic device comprising an ambient light sensor configured to mitigate the effects of dark count rate associated with avalanche photodiodes are provided. The example apparatus includes an exposed avalanche photodiode array, a dark avalanche photodiode array, and a controller. The exposed avalanche photodiode array is positioned to receive ambient light from an external environment. The dark avalanche photodiode array is obscured from the ambient light. The controller is configured to receive an exposed illumination count corresponding to the ambient light received at the exposed avalanche photodiode array. The controller is further configured to receive a dark illumination count corresponding to a dark count at the dark avalanche photodiode array. The controller determines an ambient light value based on a difference between the exposed illumination count and the dark illumination count.

This invention discloses a single-photon avalanche diode based on multi-element rare-earth co-doping and its fabrication method, aiming to solve the problems of excessively high room-temperature dark count rate caused by bulk and interface defects in existing InP / InGaAs-based SPADs, and the trade-off between core performance indicators. The core structure of the device includes an InP substrate and sequentially epitaxial layers of a buffer layer, an absorption layer, a gradient layer, a charge layer, and a multiplication layer, with at least one functional layer using two or more rare-earth co-doped materials selected from Gd. 3+ La 3+ Pr 3+ 、Nd 3+ Eu 3+ Rare-earth ion co-doping enables targeted cross-scale defect passivation and the construction of shallow trap energy level networks. This invention suppresses the dark count core generation mechanism at the intrinsic material level, synergistically improving photon detection efficiency and reducing afterpulse probability. Furthermore, the fabrication process is fully compatible with existing semiconductor production lines, facilitating industrial-scale mass production and making it suitable for fields such as quantum communication, lidar, and fluorescence lifetime imaging.