RESUMO
GaN's outstanding physical characteristics allow for a wide range of applications in numerous industries. Although individual GaN-based ultraviolet (UV) photodetectors are the subject of in-depth research in recent decades, the demand for photodetectors array is rising as a result of advances in optoelectronic integration technology. However, as a prerequisite for constructing GaN-based photodetectors array, large-area, patterned synthesis of GaN thin films remains a certain challenge. This work presents a facile technique for pattern growing high-quality GaN thin films for the assembly of an array of high-performance UV photodetectors. This technique uses UV lithography, which is not only very compatible with common semiconductor manufacturing techniques, but also enables precise patterning modification. A typical detector has impressive photo-response performance under 365 nm irradiation, with an extremely low dark current of 40 pA, a high Ilight /Idark ratio over 105 , a high responsivity of 4.23 AW-1 , and a decent specific detectivity of 1.76 × 1012 Jones. Additional optoelectronic studies demonstrate the strong homogeneity and repeatability of the photodetectors array, enabling it to serve as a reliable UV image sensor with enough spatial resolution. These outcomes highlight the proposed patterning technique's enormous potential.
RESUMO
Most of the studies focused on V2O5 have been devoted to obtaining specific morphology and microstructure for its intended applications. Two dimensional (2D) V2O5 has the most valuable structure because of its unique planar configuration that can offer more active sites. In this study, a bottom-up and low-cost method that is hydrothermal combined with spin-coating and subsequent annealing was developed to prepare 2D V2O5 nanosheets film on quartz substrate. First, VOOH nanosheets were prepared by the hydrothermal method using V2O5 powders and EG as raw materials. Further, V2O5 nanosheets with an average lateral size over 500 nm and thickness less than 10 nm can be prepared from the parent VOOH nanosheets by annealing at 350 °C for 15 min in air. The prepared V2O5 nanosheets film was assembled of multiple nanosheets. The structural, morphological, microstructural and optical properties of the films were respective investigated by XRD, SEM, TEM and UV-Vis. The photodetector based on V2O5 nanosheets film shows good photoresponse with a response time of 2.4 s and a recovery time of 4.7 s.
RESUMO
Amorphous indium zinc tin oxide (a-IZTO) is a kind of transparent conductive oxide (TCO), which can be used in transparent electrodes, transistors, and flexible devices. At present, a key limitation of a-IZTO is the costly vacuum manufacturing technology, and its commercial production is also restricted by the complex raw material preparation process. In this article, we report a liquid metal-based van der Waals (vdW) exfoliation technique by which a-IZTO films with several nanometres thickness are fabricated. The a-IZTO films fabricated in ambient air have a size on the centimeter scale and an optical transmittance of 99.64%; they are also large-area flexible oxide films. In order to illustrate the capabilities of this technology, we fabricated thin film transistors (TFTs) and photodetectors based on a-IZTO films. An a-IZTO thin film transistor (TFT) has an on/off ratio of 106. When the Vds is 5 V, the responsivity, detectivity and external quantum efficiency of an a-IZTO photodetector are 7.57 × 104 A W-1, 4.00 × 1015 Jones and 3.68 × 105%, respectively, exhibiting one of the top performances in this field.
RESUMO
Recent advances in two-dimensional (2D) materials play an essential role in boosting modern electronics and optoelectronics. Thus far, transition metal dichalcogenides (TMDs) as emerging members of 2D materials, and the van der Waals heterostructures (vdWHs) based on TMDs have been extensively investigated owing to their prominent capabilities and unique crystal structures. In this work, an original vdWH composed of molybdenum disulfide (MoS2) and platinum disulfide (PtS2) was comprehensively studied as a field-effect transistor (FET) and photodetector. A gate-tunable rectifying behavior was obtained, stemming from the band design of PtS2/MoS2 vdWH. Upon 685 nm laser illumination, it also exhibited a superior photodetection performance with a distinctly high photoresponsivity of 403 A W-1, a comparable detectivity of 1.07 × 1011 Jones, and an excellent external quantum efficiency of 7.32 × 104%. More importantly, fast rise (24 ms) and decay (21 ms) times were obtained under 685 nm light illumination attributed to the unilateral depletion region structure. Further, the photovoltaic effect and photocurrent of the heterojunction could be modulated by a back gate voltage. All these results indicated that such 2D-TMD-based vdWHs provide a new idea for realizing high-performance electronic and optoelectronic devices.
