- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Sensors, Circuits and Instrumentation Systems (2018) || Investigation of Optoelectronic Properties of Amorphous Silicon Germanium Photodetectors
摘要： Cost consideration of the development of electronic devices is one of prime importance. One simple approach to lower the cost of production of photovoltaic and detectors is by using low cost materials such as amorphous silicon and germanium. These two semiconductors have different optoelectronic properties, such as energy gap, photoconductivity and absorption coefficient. The use of an alloy from the mixing of silicon with certain percentages of germanium would produce photodetectors with improved electronic characteristics and photoconductivity. A number of a-SiGe alloy thin films with different quantities of germanium have been fabricated using thermal vacuum evaporation technique. Conduction mechanism and activation energy of the prepared samples had been calculated and analyzed. The I–V characteristics, the photogenerated current and detectivity of these samples are subjected to measurement and discussion. Hall measurements are also conducted so to calculate the Hall I–V characteristics, Hall mobility, carrier concentration and type identification of the samples.
关键词： Amorphous silicon germanium photodetector,photoconductivity,detectivity,Hall measurements,activation energy,conduction mechanism
更新于2025-09-16 10:30:52
-
Enhanced photocurrent in organic photodetectors by the tunneling effect of a hafnium oxide thin film as an electron blocking layer
摘要： To achieve high detectivity of organic photodetectors (OPDs), we investigated hafnium oxide (HfO2) as an electron blocking layer in an attempt to obtain a low leakage current and high photocurrent by the tunneling effect. The prepared devices consisted of indium tin oxide (ITO)/HfO2/(poly(3-hexylthiophene-2,5-diyl)[P3HT]:PC60BM)/Yb/Al. To explore the tunneling effect in a hafnium oxide thin film, we fabricated a thin film using successive ionic layer deposition. The results for hafnium oxide were compared with those for aluminum oxide and poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT:PSS). We found that hafnium oxide results in a low leakage current and high photocurrent owing to the tunneling effect in the OPDs. The resulting detectivity of 1.76 × 1012 Jones for a film thickness of 5.5 nm and bandwidth of ～100 kHz is suitable for commercialization.
关键词： detectivity,tunneling effect,organic photodetectors,hafnium oxide,electron blocking layer
更新于2025-09-16 10:30:52
-
Broadband polymer photodetectors with a good trade-off between broad response and high detectivity by using combined electron-deficient moieties
摘要： High-performance broadband photodetectors based on low-bandgap conjugated polymers are scarce due to a trade-off between the photoresponse range and device performance. In this work, the polymers with structural features responsible for both broad response and high detectivity are realized by using the combined electron deficient moieties at the molecular level. Based on the electron-deficient diketopyrrolopyrrole (DPP) and benzothiadiazole (BT), the combined units of DPP-DPP and DPP-BT-DPP are deemed more electron deficient and were successfully incorporated into the corresponding polymers. The arrangement of electron deficient moieties in the polymer mainchain were found to be able to greatly affect the absorption profile, energy level, molecular stacking, and blend film morphology. Consequently, the photodetector based on the polymer with DPP-BT-DPP acceptor exhibited the D* value of over 1012 Jones in the spectral region of 320–930 nm under -0.1 V bias.
关键词： low-bandgap conjugated polymers,electron deficient moieties,high detectivity,DPP,broadband photodetectors,BT
更新于2025-09-16 10:30:52
-
Size-Dependent Photoresponse of Germanium Nanocrystals-Metal Oxide Semiconductor Photodetector
摘要： In this article, size-dependent photoresponse characteristics and low-frequency noise behavior of high-speed germanium nanocrystals (nc-Ge) photodetector have been reported. The nc-Ge embedded in SiO2 matrix with different sizes have been synthesized by annealing the cosputtered Ge-SiO2 thin films at 800 ?C–900 ?C. It has been observed that the photoresponse of the detector increases with the increasing size of nc-Ge. The sample annealed at 900 ?C showed maximum responsivity (3.5 A/W) with the fast response time. The low-frequency noise spectral power density in the current fluctuation (SI) have been measured for the fabricated nc-Ge photodetectors, and lowest noise equivalent power (NEP) and highest detectivity (D?) have been observed in the nc-Ge detector synthesized at 900 ?C. Tunable responsivity in nc-Ge has been observed due to size-dependent light absorption, electric field-driven carrier separation, and tunneling through the oxide barriers. The transient photoresponse behavior has also been studied and the best rise time of 6.2 μs was observed for nc-Ge synthesized at 900 ?C. These results suggest that the nc-Ge are a promising contender for high-performance integrated optoelectronic devices that are fully compatible with silicon technology in terms of fabrication and thermal budget.
关键词： Detectivity,noise equivalent power (NEP),responsivity,noise spectral power,germanium nanocrystals (nc-Ge)
更新于2025-09-16 10:30:52
-
Impact of the Structural Parameters on the Photoresponse of Terahertz Blocked-impurity-band Detectors With Planar Structure
摘要： We fabricate germanium-based blocked-impurity-band (BIB) terahertz detectors with the same planar structure but different structural parameters. The photoresponse waveband range is about 40 - 130 μm. The best detectivity of these detectors reaches as high as 1.3 × 1013 Jones at 2.6 V and 4 K. The impact of the structural parameters, including the length of the absorbing layer (AL) and blocking layer (BL) on the performance of detectors is investigated. It is concluded that there is an optimum BL length, enabling the fabricated BIB detectors to achieve the highest sensitivity. This work highlights the importance of the optimized structural parameters and their influence on the performance of the detectors.
关键词： planar structure,Absorbing layer length,detectivity,blocked-impurity-band terahertz detectors,blocking layer length
更新于2025-09-16 10:30:52
-
Influence of PEIE interlayer on detectivity of red-light sensitive organic non-fullerene photodetectors with reverse structure
摘要： In this work we analyse an influence of 80 % ethoxylated polyethyleneimine (PEIE) interlayer modifying the ITO electrode work function on the detectivity and time response of the red-light sensitive photodetectors based on donor-acceptor copolymer HFQx-T (where HFQx stands for hexafluoroquinoxaline acceptor units, and T for benzodithiophene derivative donor blocks) blended with acceptor ITIC (with indacenodithieno[3,2-b]thiophene as central donor unit and 2-(3-oxo-2,3-dihydroinden-1-ylidene) malononitrile as acceptor end groups). Modification of ITO electrode by PEIE interlayer allows to construct the photodiode with reversed structure which results in low dark current and high detectivity of the photodetector. The 3.5 nanometres thick PEIE interlayer causes strong reduction of the dark current in comparison to the dark current measured in classical photodiode structure; this allowed to obtain remarkably high detectivity, exceeding 2×1013 Jones. However, a presence of the PEIE interlayer has significantly lengthen the photodiode time response. We demonstrate that when designing the photodiodes with reversed structure, one should consider compromise between the required detectivity and the time response of the photodetector.
关键词： organic photodiode with reverse structure,ethoxylated polyethyleneimine,photodetector detectivity,photodetector time response,PEIE,organic photodetector
更新于2025-09-12 10:27:22
-
Solution Processed MoS<sub>2</sub> Quantum Dots/GaAs Vertical Heterostructures based Self-powered Photodetectors with Superior Detectivity
摘要： The characteristics of a novel 0D/3D heterojunction photodetector fabricated using solution processed colloidal MoS2 quantum dots (QDs) on GaAs is being presented. MoS2 QDs with a dimension of ~2 nm, synthesized by standard sono-chemical exfoliation process of 2D layers have been used for the purpose. The microscopic and spectroscopic studies confirmed the formation of semiconducting (2H phase) MoS2 QDs. The photodetectors were fabricated using n-GaAs substrates with two different doping concentrations resulting in n-n heterojunctions between n-type 0D MoS2 QDs and bulk n-GaAs. The devices fabricated using GaAs having higher doping concentration, upon illumination, showed an increase of reverse current of the order of ~102, while the same with lower doping concentration showed an increase of the order of ~103. All the heterojunction photodetector devices show a broadband operation over the visible wavelength range of 400 – 950 nm, with a peak responsivity of the devices being observed at 500 nm. The peak responsivity and detectivity are found to be ~400 mA/W and ~4 × 1012 Jones, respectively even without any external applied bias, which are useful for self-powered photodetection. Results indicate that colloidal MoS2/GaAs based hybrid heterostructures provide a platform for fabricating broadband photodetectors by using highly absorbing MoS2 QDs, which may show the pathway towards next-generation optoelectronic devices with superior detection properties.
关键词： MoS2,detectivity,quantum dots,photodetectors,vertical heterostructure,GaAs
更新于2025-09-12 10:27:22
-
Ultrasensitive Organic‐Modulated CsPbBr <sub/>3</sub> Quantum Dot Photodetectors via Fast Interfacial Charge Transfer
摘要： The integration of organic materials with colloidal quantum dots (QDs) has the merits the advantages of the molecular diversity and photoelectric tunability for ultrasensitive photodetector applications. Herein, a uniform CsPbBr3 QD layer is sandwiched between the same poly-(N, N′-bis-4-butylphenyl-N, N′-bisphenyl) benzidine (Poly-TPD) and phenyl-C61-butyric acid methyl ester (PCBM) (1:1) organic blend films. The CsPbBr3 QD layer efficiently absorbs the excitation light, where the generated exciton can sufficiently diffuse to the interface of QD and organic blend layers for efficient charge separation and effective gate modulation. Owing to the desirable heterojunction at the interface, the dark current is substantially suppressed, while the photocurrent is increased in comparison with those of pristine QDs photodetectors. The ultrafast charge transfer time (≈300 ps) from QDs to organic blend layer measured by the time-resolved transient absorption spectroscopy is potentially benefit the enhanced electron–hole pair dissociation. The solution-processed, organic (Poly-TPD:PCBM blend)-modulated CsPbBr3 QDs photodetector are exhibited ultrasensitive photoresponse abilities in terms of in terms of noise equivalent power (NEP = 1 × 10?16 W Hz?0.5), ILight/IDark ratio (2 × 103), and the a specific detectivity (D* = 4.6 × 1013 Jones). The results will be a starting point for ultrasensitive next-generation light detection technologies.
关键词： detectivity,organic materials,solution-processed,photodetectors,perovskite quantum dots
更新于2025-09-12 10:27:22
-
Ultrasensitive ZnO Nanowire Photodetectors with a Polymer Electret Interlayer for Minimizing Dark Current
摘要： Zinc oxide (ZnO) nanowires have attracted extensive interests in ultraviolet photodetection fields owing to their outstanding optoelectronic properties. The detectivity of ZnO nanowire photodetectors is often limited by large dark current due to a number of defect-induced carriers. Herein, a thin layer of poly(2-vinyl naphthalene) (PVN) is introduced between the ZnO nanowire and gate dielectric to deplete defect-induced carriers with the help of the electrostatic field generated by trapped electrons in the PVN layer. The dark current is successfully reduced from 2.2 × 10?9 to 1.6 × 10?14 A. Particularly, ZnO nanowire photodetectors with a large Ilight/Idark ratio (>107), high photoresponsivity (>106 A W?1), and ultrahigh detectivity (>1018 Jones) are achieved, which are among the best performance in reported ZnO-based photodetectors. The present simple scheme offers a new strategy to suppress dark current in semiconducting nanomaterials for ultrasensitive photodetection applications.
关键词： polymer electret,detectivity,ultraviolet photodetection,ZnO nanowires
更新于2025-09-12 10:27:22
-
Wearable Gallium Oxide Solar-blind Photodetectors on Muscovite Mica Having Ultra-High Photoresponsivity And Detectivity With Added High Temperature Functionalities
摘要： Wearable Gallium oxide solar-blind photodetector fabricated on muscovite mica is reported for room temperature as well as high temperature operations. The ultra-high photoresponsivity of 9.7 A/W is obtained for 5V applied bias at room temperature under 75 μW/cm2 weak illumination of 270 nm wavelength. The detector enables very low noise equivalent power (NEP) of 9×10-13 W/Hz1/2 and ultra-high detectivity of 2×1012 jones which shows the magnificent detection sensitivity. Further, bending tests are performed for robust utilization of flexible detectors up to 500 bending cycles with each bending radius of 5 mm. After 500 bending cycles, device shows slight photocurrent decrease. The bending performances exhibit excellent potential for wearable applications. Moreover, photocurrent and dark current characteristics above room temperature demonstrate the outstanding functionalities till 523K temperature which is remarkable for flexible photodetectors. The obtained results show the potential of Gallium oxide solar-blind photodetectors at room temperature and high temperatures environments which pave the ways for futuristic smart and flexible sensors.
关键词： photoresponse,Gallium Oxide,Solar-blind photodetectors,detectivity,flexible photodetector,Mica
更新于2025-09-11 14:15:04