Search

Antimonene, a promising conductor for next-generation 2D-based devices, has its contact resistance significantly influenced by the van der Waals (vdW) interaction within its heterostructure. In this study, we report the quantification of the vdW coupling between multilayer antimonene and bilayer MoS2 by ultrafast coherent vibration spectroscopy. By utilizing a femtosecond laser, we excited coherent acoustic vibrations in the multilayer-antimonene on substrate-supported bilayer MoS2, and the relative displacement at the vdW heterojunction was detected with the aid of bilayer MoS2. The photoexcited strain pulse generated in the multilayer-antimonene was observed as it transported to the bilayer MoS2, explaining the distortion at the beginning of the oscillation. By analyzing the thickness-dependent oscillation frequencies, we determine the effective vdW elastic constant between multilayer-antimonene and MoS2 to be (1.9 ± 0.2) × 1018 N/m3. This non-destructive optical technique offers a significant advance in the evaluation of vdW interactions at 2D metal-semiconductor interfaces. [ABSTRACT FROM AUTHOR]

Short‐wave infrared (SWIR) photodetectors utilizing quantum dot (QD) material systems, harnessed through the quantum confinement effect to tune the absorption wavelength, offer an attractive avenue for the development of cost‐effective and solution‐processed photodetectors compared to the relatively expensive compound semiconductor photodetectors. However, the pores between the QDs and poor chemical stability after surface modification have impeded the practical application of quantum‐dot‐based photodetectors. In this study, high‐gain SWIR photodetector is demonstrated and achieved by incorporating PbS QD into the Cs2AgBiBr6 halide‐based double perovskite matrix, as confirmed by X‐ray diffraction, transmission electron microscope, and energy dispersive spectrometer. The thin film structure and detailed local structure are revealed by 2D grazing‐incidence wide and small‐angle X‐ray scattering. The resulting PbS@Cs2AgBiBr6‐based SWIR photodetector exhibits remarkable performance with a responsivity and detectivity of 15000 A W−1 and 1.31 × 1012 cm Hz1/2 W−1, respectively. This study offers valuable insights into the design of composite materials for high‐gain SWIR photodetectors. [ABSTRACT FROM AUTHOR]

The development of semiconductor optoelectronic devices is moving toward low power consumption and miniaturization, especially for high-efficiency quantum emitters. However, most of these quantum sources work at low carrier density regions, where the Shockley–Read–Hall (SRH) recombination may be dominant and seriously reduce the emission efficiency. In order to reduce the effect of carrier trapping and sustain a strong photoluminescence (PL) emission under low power pumping conditions, we investigated the influence of "suspending" a monolayer of tungsten diselenide (WSe2), a novel two-dimensional quantum material. Not only the PL intensity but also the fundamental photoluminescence quantum yield (PLQY) has exhibited a huge, order-scale enhancement through suspending; even surprisingly, we found the PLQY improvement to be far significant under small pumping powers and observed an exponential increase in tendency toward an even lower carrier density region. With its strong excitonic effect, suspended WSe2 offers a solution to reduce carrier trapping and participate in non-radiative processes. Moreover, in the low-power range, where SRH recombination dominates, suspended WSe2 exhibited a remarkably higher percentage of excitonic radiation compared to contacted WSe2. Herein, we quantitatively demonstrate the significance of the suspended WSe2 monolayer in a low carrier density region, highlighting its potential for developing compact, low-power quantum emitters in the future. [ABSTRACT FROM AUTHOR]

Short‐wave infrared (SWIR) quantum dot (QD)‐converted photodetectors are one of the promising devices used in artificial intelligence and automatic navigation systems. However, compared to semi‐conductor‐type photodetectors, they suffer from poor chemical stability and weak electronic conductivity. In this study, a PbS QD and conductive metal–organic framework (MOF) hybrid composite is designed with SWIR detection capability. The Fourier‐transform infrared spectroscopy confirms the surface modification of PbS QDs with MOF. X‐ray absorption near‐edge structures spectra reveal the chemical bonding between MOF and PbS QDs. Furthermore, 2D grazing‐incidence small‐ and wide‐angle X‐ray scattering is utilized to unveil the particle stacking and the preferred orientation of the PbS@MOF thin film. By integrating the PbS@MOF thin film directly on top of the graphene field effect transistor (FET) device, the chemical stability and photoelectric properties of graphene FET are enhanced, and these are investigated using a focus ion beam with a high‐resolution transmission electron microscope. This study offers a strategy to simultaneously improve the chemical stability and the photoelectronic properties of the nanomaterials as well as contribute to the advancement of a QD‐converted SWIR photodetector. [ABSTRACT FROM AUTHOR]

Double-side-emission (DSE) CdSe@CdZnSeS/ZnS quantum dot (QD) light-emitting diodes (DSE-QLEDs) with transparent nanometer-thick metal electrodes were achieved by monolayer (ML) MoS2-mediated van der Waals (vdW) epitaxy. Via the transfer of a wafer-area MoS2 film from sapphire to polyethylene terephthalate (PET) substrates and ZnO nanoparticle (NP) layer surfaces, flexible red DSE-QLEDs with the structure of MoS2/Au/M-PEDOT:PSS/poly-TPD/QD/ZnO NP/MoS2/Al can be readily obtained by spin-coating and thermal evaporation. The unique van der Waals epitaxy on MoS2 surfaces greatly helps the lateral film formation for both nanometer-thick Au films on flat PET substrates and Al films on the rough ZnO layer surface. The conductive Au and Al films grown on MoS2 surfaces act as effective anode and cathode electrodes for current injections of the QLEDs, respectively, while the ML MoS2 contributes to the balance of injected charges by suppressing the electron injection rate. Finally, with the 10 nm-thick Au anode and 15 nm-thick Al cathode, our flexible DSE-QLEDs exhibit a subthreshold turn-on voltage of 1.8 V, a maximum luminance of ∼83000 cd/m2, and a current efficiency of 31.9 cd/A, in which approximately 36% of total luminance is contributed from the Al cathode side emission. [ABSTRACT FROM AUTHOR]

The exploration of functional light-emitting devices and numerous optoelectronic applications can be accomplished on an elegant platform provided by rapidly developing transition metal dichalcogenides (TMDCs). However, TMDCs-based light emitting devices encounter certain serious difficulties, such as high resistance losses from ohmic contacts or the need for complex heterostructures, which restricts the device applications. Despite the fact that AC-driven light emitting devices have developed ways to overcome these challenges, there is still a significant demand for multiple wavelength emission from a single device, which is necessary for full color light emitting devices. Here, we developed a dual-color AC-driven light-emitting device by integrating the WSe2 monolayer and AlGaInP–GaInP multiple quantum well (MQW) structures in the form of capacitor structure using AlOx insulating layer between the two emitters. In order to comprehend the characteristics of the hybrid device under various driving circumstances, we investigate the frequency-dependent EL intensity of the hybrid device using an equivalent RC circuit model. The time-resolved electroluminescence (TREL) characteristics of the hybrid device were analyzed in details to elucidate the underlying physical mechanisms governing its performance under varying applied frequencies. This dual-color hybrid light-emitting device enables the use of 2-D TMDC-based light emitters in a wider range of applications, including broad-band LEDs, quantum display systems, and chip-scale optoelectronic integrated systems. [ABSTRACT FROM AUTHOR]

We demonstrate in-plane gate transistors based on the molybdenum disulfide (MoS2)/graphene hetero-structure. The graphene works as channels while MoS2 functions as passivation layers. The weak hysteresis of the device suggests that the MoS2 layer can effectively passivate the graphene channel. The characteristics of devices with and without removal of MoS2 between electrodes and graphene are also compared. The device with direct electrode/graphene contact shows a reduced contact resistance, increased drain current, and enhanced field-effect mobility. The higher field-effect mobility than that obtained through Hall measurement indicates that more carriers are present in the channel, rendering it more conductive. [ABSTRACT FROM AUTHOR]

The main purpose of this study is to investigate the impact of service quality and corporate social responsibility (CSR) on customer satisfaction, and customer satisfaction toward post-purchase intentions from sheltered employment institutions. Work experience plays an important role in career development for those people with intellectual disabilities. When they are not yet capable of obtaining a job in the open market, they must receive job training and daily care in sheltered employment institutions. If the sheltered employment institutions cannot operate properly, they will greatly affect intellectual disabilities. From the study of "Children Are Us Bakeries and Restaurants" sheltered employment institutions are one kind of food service business that has been found to request and improve service quality and execution of CSR. These are two main factors which can enhance brand value and create a good reputation for sheltered employment institutions. The questionnaire results indicate that perceived service quality has a positive relationship with customer satisfaction and the reliability dimension is the most important factor for customers to assess service quality. Meanwhile, correlation analysis shows that customer satisfaction regarding service quality influences post-purchase intentions, indicating that friendly and helpful employees can please customers and enhance their satisfaction level and also induce positive post-purchase intentions of consumers. Regarding the CSR of "Children Are Us Bakeries and Restaurants" sheltered employment institutions, the analysis reveals a statistical significance: the greater customer satisfaction of CSR, the higher the post-purchase intention. In addition, in the work, paired-sample t test analysis reveals there is a significant difference (p less than 0.05) in service quality and CSR in terms of "perceived" and "expected" responses. In summary, since those with intellectual disabilities usually are enthusiastic at work and do their best to provide good service and execute CSR well, the value of sheltered employment institutions establishments should be recognized by all should receive continued support and there should be a willingness to hire these intellectually disabled citizens. (Contains 6 tables.)

The main purpose of this study was to investigate the impact of rope jumping exercise on the health-related physical fitness of visually impaired students. The participants' physical fitness was examined before and after the training. The exercise intensity of the experimental group was controlled with Rating of Perceived Exertion (RPE) (values ranging from 11 to 15), while the control group did not participate in the exercise. A dependent samples "t"-test indicated significant differences in both groups between pre- and post-training. Through ANCOVA analysis, there was a significant difference (p less than 0.05) in the flexibility and aerobic capacity for the experimental group and a significant improvement on their physical fitness (p less than 0.05). (Contains 5 tables.)