RESUMEN
Silicon (Si), the dominant semiconductor in microelectronics yet lacking optoelectronic functionalities in UV regions, has been researched extensively to make revolutionary changes. In this study, the inherent drawback of Si on optoelectronic functionalities in UV regions is potentially overcome through heterostructure coupling of delaminated p-type MnPS3, having bulk, multiple-layer, and few-layer features, with n-type Si. By artificially mimicking the architectures of shrubs with unique UV shading phenomena, the revolutionary multiple-layer MnPS3 structures with staggered stacking configurations trigger outstanding UV photosensing performances, displaying an average EQE value of 1.1 × 103%, average photoresponsivity of 3.1 × 102 A/W, average detectivity of 1.9 × 1014 cm Hz1/2W1-, and average on/off ratio of 1.8 × 103 under 365 nm light. To the best of our knowledge, this is the first attempt toward realizing gate-free MnPS3-based UV photodetectors, while all of the photodetection outcomes are better than those of more sophisticated field-effect transistor (FET) designs, which have remarkable impacts on the practicality and functionality of next-generation UV optoelectronics.
RESUMEN
Rapid, reliable, and sensitive colorimetric detection has been regarded as a highly potential technique for visually monitoring the cation ions. Yet, insight into detection kinetics and quantitative analysis for colorimetric sensing of sodium ions has rarely been revealed. Herein, in-depth kinetic investigations of colorimetric detection using surface-modified Au-nanoparticle (AuNP) probes were performed for interpreting the correlation of salt concentration, reaction duration, and light absorbance. To envision these undisclosed issues, modification of AuNP surfaces with ascorbic acid was found to be highly essential for boosting the detection sensitivity due to adjusting the zeta potential of AuNP colloids towards a slightly positive value. Next, modeling the light absorbance of AuNPs under various aggregation circumstances was employed, which visually elucidated the color change so that it was visible to the naked eye, due to the intense field localization on the edges of aggregated AuNPs. In addition, the involved activation energy of AuNP aggregation was found to follow the first-order Arrhenius formula, with the extracted value of 22.5 kJ mol-1. Finally, quantitative visualization of colorimetric Na+ ion sensing was realized, and the experimental relation was obtained for explicitly determining the unknown concentration of Na+ ions in a visual manner.
RESUMEN
Metal-assisted chemical etching (MaCE) has been widely employed for the fabrication of regular silicon (Si) nanowire arrays. These features were originated from the directional etching of Si preferentially along <100> orientations through the catalytic assistance of metals, which could be gold, silver, platinum or palladium. In this study, the dramatic modulation of etching profiles toward pyramidal architectures was undertaken by utilizing copper as catalysts through a facile one-step etching process, which paved the exceptional way on the texturization of Si for advanced photovoltaic applications. Detailed examinations of morphological evolutions, etching kinetics and formation mechanism were performed, validating the distinct etching model on Si contributed from cycling reactions of copper deposition and dissolution under a quasi-stable balance. In addition, impacts of surface texturization on the photovoltaic performance of organic/inorganic hybrid solar cells were revealed through the spatial characterizations of voltage fluctuations upon light mapping analysis. It was found that the pyramidal textures made by copper-induced cycling reactions exhibited the sound antireflection characteristics, and further achieved the leading conversion efficiency of 10.7%, approximately 1.8 times and beyond 1.2 times greater than that of untexturized and nanowire-based solar cells, respectively.
RESUMEN
Facile, effective and reliable etching technique for the formation of uniform silicon (Si) nanowire arrays were realized through the incorporation of back substrates with metal-assisted chemical etching (MaCE). In comparison with conventional MaCE process, a dramatic increase of etching rates upon MaCE process could be found by employing the conductive back substrates on p-type Si, while additionally prevented the creation of nanopores from catalytic etching reaction. Examinations on the involving etching kinetics, morphologies, wetting behaviors and surface structures were performed that validated the role of back substrates upon MaCE process. It was found that the involved two pathways for the extraction of electrons within Si favored the localized oxidation of Si at Si/Ag interfaces, thereby increasing the etching rate of MaCE process. This back-substrate involved MaCE could potentially meet the practical needs for the high-yield formation of Si nanowire arrays.
