RESUMEN
All-dielectric metasurfaces offer a promising way to control amplitude, polarization, and phase of light. However, ultraviolet (UV) component metasurfaces are rarely reported due to significant absorption loss for most dielectric materials and the required smaller footprint or feature size. Here, we demonstrate broadband UV focusing and routing in both transmission and reflection modes in simulations by adopting aluminum nitride (AlN) with ultrawide bandgap and a waveplate metasurface structure. As for experiments, the on-axis, off-axis focusing characteristics in transmission mode have been investigated at representative UVA (375 nm) wavelength for the first time, to the best of our knowledge. Furthermore, we fabricated a UV transmission router for monowavelength, guiding UV light to the designated different spatial positions of the same or different focal planes. Our work is meaningful for the development of UV photonics components and devices and would facilitate the integration and miniaturization of UV nanophotonics.
RESUMEN
Conventional metal-semiconductor-metal (MSM) ultraviolet (UV) detectors have the disadvantage of limited adjustable structural parameters, finite electrical field, and long carrier path. In this Letter, we demonstrate a three-dimensional (3D) MSM structural AlN-based deep-UV (DUV) detector, fabricated through simple trench etching and metal deposition, while flip bonding to the silicon substrate forms a flip-chip 3D-MSM (FC-3DMSM) device. 3D-MSM devices exhibit improved responsiveness and response speed, compared with conventional MSM devices. Time-dependent photoresponse of all devices is also investigated here. The enhanced performance of the 3D-MSM device is to be attributed to the intensified electrical field from the 3D metal electrode configuration and the inhibition of the carrier vertical transport, which unambiguously increases the carrier collection efficiency and migration speed, and thus the responsivity and speed as well. This work should advance the design and fabrication of AlN-based DUV detectors.
RESUMEN
The metasurface promises an unprecedented way for manipulating wavefronts and has strengths in large information capacity for the hologram. However, strong absorption loss for most dielectric materials hinders the realization of such a metasurface operating in the ultraviolet (UV) spectrum. Herein, aluminum nitride (AlN) with an ultrawide bandgap has been utilized as the material of the UV metasurface for multi-plane holography, increasing the information capacity and security level of information storage simultaneously. The metasurface for multi-plane holography achieving a correlation coefficient of over 0.8 with three reconstructed images has been investigated, and also the single-plane holography at an efficiency of 34.05%. Our work might provide potential application in UV nanophotonics.
RESUMEN
With the penetration of semiconductor lighting, GaN-based white-light-emitting diodes (WLEDs) with a high color-rendering index (CRI) and simultaneous high luminous efficiency (LE) are required, especially for high-quality indoor lighting. Here, by adopting metal nanoparticles (Ag and Au NPs) into hybridized color conversion material composed of broadband LuAG:Ce phosphor and narrowband CdSe/ZnS red quantum dots, we have fabricated AgAu-WLEDs with simultaneously increased LE (12% increment at 40 A/cm2) and CRI (maximum of 94.5), and decreased correlated color temperature (CCT, from CCT=6000 K to = 4800 K), compared with WLEDs without metal NPs. This improved performance of WLEDs is ascribed to increased color conversion efficiency brought from localized surface plasmon resonance and thus a strong resonant light scattering effect from the incorporated metal NPs. We believe the approach reported in this work will find its application in GaN WLEDs, thus advancing the development of high-efficiency and quality semiconductor lighting.
RESUMEN
Although much progress has been made on lattice plasmon mode (LPM), there is still a lack of systematic studies on LPM generation; questions remain unanswered on topics such as high-order LPM generation, LPM generation from near-coupling complex elements, and modulation of incidence energy. Here, we systematically evaluated the properties of multiple high-order LPM, energy flow modulation of incident polarization, element, angle of incidence, and hybrid of dual lattice using the finite-difference time-domain method. This study presents a clear illustration of LPM and will help on further development of LPM and plasmonics-based fields.
RESUMEN
Surface anti-reflection (AR) with nanometer-scaled texture has shown excellent light trapping performance involving optical devices. In this work, we developed a simple and lithography-free structure replication process to obtain large scale surface cup-shaped nano-pillar (CSNP) arrays for the first time. A method of depositing was used for pattern transfer based on PMMA pre-coated through-hole anodic aluminum oxide (AAO) thin film (~500 nm), and eventually, the uniformity of the transferred nanostructures was guaranteed. From the spectrum (250 nm~2000 nm) dependent measurements, the CSNP nanostructured Si showed excellent AR performance when compared with that of the single-polished Si. Moreover, the CSNP was found to be polarization insensitive and less dependent on incidence angles (≤80°) over the whole spectrum. To further prove the excellent antireflective properties of the CSNP structure, thin film solar cell models were built and studied. The maximum value of Jph for CSNP solar cells shows obvious improvement comparing with that of the cylinder, cone and parabola structured ones. Specifically, in comparison with the optimized Si3N4 thin film solar cell, an increment of 54.64% has been achieved for the CSNP thin film solar cell.