Session Index

In this work, various morphologies of CsPbBr3 quantum dots were prepared using the hot-injection method. The successful realization of single-layer quantum dot light-emitting diodes (LEDs) was achieved. Furthermore, different morphologies of quantum dots were stacked in heterojunctions, and effectively and easily enhancing carrier injection.

  Preview abstract

The study examines thermal modification and the z-scan technique for measuring optical nonlinearity. Thermal modification involves heat-induced property changes, widely used in fields like materials science. z-scan analyzes light intensity on a focal plane to study material behavior. Glass's nonlinear absorption was measured using z-scan, yielding absorption coefficient β. This β aided simulating glass modification by temperature estimation. Results showed nonlinear absorption governing material heating. Simulations confirmed laser pulse's effectiveness in modifying glass across its thickness.

  Preview abstract

Utilizing the Pancharatnam-Berry (PB) phase as means of phase modulation in metasurfaces is an effective strategy. However, signals subjected to PB phase modulation commonly manifest symmetric characteristics within circular polarization (CP), which can diminish the signal-to-noise ratio for specific CP states. In this study, an all-dielectric chiral metasurface is harnessed in conjunction with principles of topological photonics to disrupt the CP symmetry in metasurfaces, thereby enhancing the signal-to-noise ratio in far-field.

  Preview abstract

Recently, there has been a significant surge in research on two-dimensional transition metal dichalcogenide (TMDC) semiconductor lasers. Our approach involves a specialized method wherein we integrate a metal ring atop WSe2 and pair it with a silicon nitride microdisk resonator. This unique combination gives rise to a hybrid mode that merges the whispering-gallery-mode (WGM) with the surface plasmon mode. As a result, it leads to an enhanced overlap with the monolayer WSe2 and ensures a favorable quality factor. It is expected that this work will contribute to significant breakthroughs in optical communication and quantum technology fields.

  Preview abstract

An ion-gel film consisting of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) and poly(vinylidene fluoride) (PVDF) was used as a dielectric layer to fabricate poly-[2,5-bis(3-tetradecyl-thiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT)-based TFTs. The ferroelectricity of the ion-gel film is enhanced by the addition of [EMIM][TFSI] into PVDF. The devices can operate at ultralow voltage as a result of the formation of electric double layer. With the ion migration and ferroelectric properties of the ion-gel film, the devices are able to perform a variety of synaptic behavior.

  Preview abstract

1-T phase Vanadium Disulfides (VS2) has metallic property[1], compare to its semiconductive 2-H phase. We synthesized VS2 with VLS method and salt-assisted precursors through APCVD[2]. Then we confirmed our VS2 belongs to 1-T phase semimetal material through TEM and temperature-dependent I-V measurement. We transferred VS2 on WS2 to build VS2/WS2 heterostructure. We identified VS2 and WS2 in heterostructure with Raman measurement and OM image. From now on, we experimented semimetal bismuth perform as contact material. Compare to chromium, bismuth contact shows ohmic contact and lower contact resistance. In future, VS2/WS2 heterostructure would experiment to compare with bismuth contacts.

  Preview abstract

A comprehensive understanding of fluorescence properties in cellulose films is required to advance cellulosic fluorescence films. We acquired the fluorescence properties including the quantum yields, lifetimes, and rates of the radiative k_r and nonradiative k_nr decay of fluorescein isothiocyanate (FITC) and FITC-labeled cellulose (FLC) in methanol, ethanol, and aqueous solutions as well as FLC films. The fluorescence quantum yields of FLC are found to be very low compared to those of other samples, which may be more significantly caused by anomalously reduced k_r of FLC than increased k_nr.

  Preview abstract

We present ethanol-assisted photoreduction synthesis of silver nanoparticles (Ag NPs) on the UVC illuminated ferroelectric templates for the SERS application. The ethanol-assisted photoreduction not only increases the density of silver seeds but also enhance the growth rate of Ag NPs. A large amount of Ag NPs produce high-density hotspots, which can effectively enhance the Raman signal intensity of analytes by electromagnetic mechanism. Compared with the sample prepared without ethanol assistance, the Raman signal intensity can be enhanced by 4.87 times. The prepared SERS substrate has an ultra-low limit of detection 1.47×10^-9 M and a high enhancement factor of 2.34×10^9.

  Preview abstract

This research discusses Schottky mid-infrared (MIR) photodetector (PD), where the probability of hot carrier crossing Schottky barrier is enhanced by adjusting hot carrier diffusion distance. A mathematical model is employed to validate experimental results of hot carrier diffusing to and leaping over the barrier, thereby improving the responsivity of the device. As a result, for Ag thin film thickness of 20 nm, the response at 3.46 μm wavelength is 6.46 times higher than the device with 10 nm thickness.

  Preview abstract

In this study, nonahydrated aluminum nitrate was used as the source of aluminum.
The aluminum was mixed with zinc oxide and then grown using a hydrothermal method to form
zinc oxide nanorods as the electron transport layer. The performance of the perovskite solar
cells based on non-doped and 1% Aluminum-doped zinc oxide nanorods was compared, and it
was found that the device with aluminum doping exhibited the higher efficiency.

  Preview abstract

A plasmon thin film transistor of Al2O3/ZnO/HfO2 channel is deposited on ITO substrate by atomic layer deposition. Au nanostructures are formed on the channel surface by as-deposited 3nm gold thin film. The as-deposited Au nanostructures in air (n =1) absorb incident light of = 680nm, and the photo-generated hot carriers are amplified by the TFT to reach a high responsivity of R = 2.1 A/W. When the Au nanostructures coated by refractive index oil n = 1.64, the responsivity peak R = 1.2 A/W is red-shifted to near-infrared  = 730nm.

  Preview abstract

The PEDOT/WO3/ZnO porous film were prepared with electrochemical polymerization, sputtering, and hydrothermal method for energy-saving window applications. The electrochromic analysis showed that the composite film exhibited a contrast ratio of 42.8% at wavelength 650 nm, with high ion diffusion coefficient and rapid response during coloring (2.8 s) and bleaching (1.3 s). After 50 redox cycles, the current density of the composite film decreased by 18.8%. However, a stable response was observed when the number of cycles was further increased. The coloration efficiency of the PEDOT/WO3/ZnO was 54.48 cm2/C, which was better than the film prepared with a WO3/PEDOT/ZnO structure.

  Preview abstract

Besides the crystallinity of the grown MoS2, high contact resistance at electrode/ MoS2 interface and the inferior influence from the dielectric layer are also possible mechanisms responsible for the inferior performances of MoS2 transistors. Through the improvement of the crystallinity of the au electrodes, sequential film transferring instead of direct bi-layer MoS2 growth and the isolation of the MoS2 channel from the SiO2 dielectric layer, the MoS2 transistor with enhanced field-effect mobility values from 0.27 to 1.33 cm2V-1∙s-1 is observed. High ON/OFF ratio 100000 is also observed. The possibility of scalability is advantageous for the practical applications of 2D materials.

  Preview abstract

In this work, we analyze the Si-based germanium IR photodetector that we have fabricated. Due to the difference in lattice constants between germanium and silicon, there is great difficulty in high-quality germanium epitaxial. Therefore, we fabricated a thin-film PIN photodiode with a rocky top silicon layer. We analyzed the device and thin-film deposition with scanning electron microscopy (SEM). The quality of the deposited material was analyzed by Raman analysis, and the optical properties were measured and analyzed.

  Preview abstract

This study introduces a novel method of passivating perovskite quantum dots (PQDs) using Al2O3 and atomic layer deposition (ALD). This technique shields PQDs from moisture, oxidation, and temperature changes, maintaining their stability and reliability. It exhibits robust performance in various tests including long-term lighting aging and temperature/humidity conditions (60°/90%). By integrating with micro-LED and red phosphor, we fabricated a white light system with a data transmission rate of 1 Gbit/s. This approach opens promising avenues for full-color micro-displays and high-speed visible light communication (VLC) applications, offering a significant advancement in PeQDs passivation.

  Preview abstract

In this study, we demonstrate the fabrication of microring resonators using nanoimprint technology. Silicon nitride (SiN) resonators with high quality (Q) factors up to the order of 105 can be realized by nanoimprinting lithography (NIL). In addition, by properly
designing the waveguide geometry, nearly-zero waveguide dispersion can be achieved. This work offers the promising potential to fabricate microring resonators in a significantly costeffective and process-friendly scheme.

  Preview abstract

In recent years, with the rise of artificial neural networks, researchers have developed devices using halide perovskites for artificial synapses. Lead halide perovskites have shown successful applications, but their toxicity limits future development. To address this, we used eco-friendly Cs3Bi2I9-xBrx as the active layer, achieving superior performance in Cs3Bi2I6Br3 (x = 3) with improved crystallinity, reduced dark current, and optimal synaptic behavior. It shows promise for efficient artificial synaptic applications.

  Preview abstract

In the present work, we theoretically study the optical multistability in a hybrid system consisting of an optomechanical cavity with quantum dot molecules inside it coupled to an auxiliary cavity via a single-mode waveguide. We obtain the expression for the primary cavity photon number by solving the Heisenberg-Langevin equations of motion in the steady state limit, which indicates the presence of optical multistability phenomena in the proposed system. We show that various system parameters can control and modulate the optical multistability curves, which can be utilized for designing and optimizing sensitive all-optical switching devices at low power and optical sensors.

  Preview abstract

We experimentally demonstrate the first period-chirped silicon blazed gratings by laser interference lithography and wet chemical etching. The resultant gratings have a period change over 110 nm that enables more than 200 nm of wavelength coverage when it serves as the dispersive element to resolve the incident light spectrum.

  Preview abstract

In this study, we utilized molecular beam epitaxy to grow the Type-II superlattice (T2SL) structure. By adjusting the Arsenic flux during the growth of the InAs layer, we investigated the influence of the V/III ratio on photoluminescence and x-ray diffraction of SWIR T2SL. X-ray diffraction patterns indicated an enhanced strain control down to 0.07%. The low-temperature photoluminescence analysis revealed that the sample with a lower V/III Ratio exhibited higher luminescence intensity. The findings from both measurements underscore the importance of adjusting the V/III Ratio for the InAs layer during the growth of the T2SL structure.

  Preview abstract

This study explores the extension of quantum dot (QD) wavelength to approximately 1.38 μm on GaAs substrates. Utilizing molecular beam epitaxy (MBE), we investigate the impact of InGaAs strained buffer layer (SBL) thickness on InAs Quantum Dots (QDs). Photoluminescence (PL) spectra reveal a redshift and narrower FWHM value as SBL thickness increases. Atomic force microscopy (AFM) analysis demonstrates a clear trend between SBL thickness and quantum dot density. Optimal SBL thickness enhances uniformity and density, promising applications in facial recognition, automotive lidar, and optical communication.

  Preview abstract

Metamaterial-based nanophotonic devices were numerically analyzed using the FDTD method to study polarization converters with high transmission and wide bandwidth in the optical and terahertz frequency ranges. First, the transmission characteristics of the incident polarization angle of the proposed polarization converter in the optical frequency band were investigated, and it was found that the transmitted light becomes clockwise circularly polarized when the incident linearly polarized light is 45°. Furthermore, similar results were obtained in the terahertz band, and a high-performance polarization converter was realized.

  Preview abstract

InGaN-based Green vertical cavity surface emitting laser structure had been demonstrated with top dielectric reflector and bottom porous distributed Bragg reflector (DBR). The electroluminescence (EL) spectra of the InGaN device without and with top dielectric mirrors were analyzed. The central wavelength and stopband width of porous DBR structure were measured at 522nm/75nm with 66.3 nm-thick porous GaN and 58.7 nm-thick non-etched GaN layer of the 20-pair stack structure. For the VCSEL structure, the line width of the ST-LED structure was reduced from 34.5 nm at 509.7 nm and 2.18 nm at 520.8 nm for the VCSEL structure.

  Preview abstract

The photo-electrical and synaptic properties of flavin-doped DNA biopolymer devices are presented. The wavelength-dependent electric characteristics and the implementation in neuromorphic computing are demonstrated, which may facilitate the development of biomaterial-based devices with neuromorphic functionalities.

  Preview abstract

The plasmonic resonance characteristics of heavily Ga-doped ZnO (GaZnO) epilayers grown with sapphire substrate temperatures 235, 250, and 265 oC corresponding to Ga doping concentration 4.6, 3.5, and 3.0 at.% of molecular beam epitaxy (MBE) are explored. Hall effect measurements of epilayers show that free electron concentration reaches around 1021 cm−3. The plasmonic resonance wavelength are 1377, 1385, 1436 nm for Ga doping concentration 4.6, 3.5, and 3.0 at.%, respectively. Lower strain, loss, and surface roughness are observed in sample with doping concentration 3.5 at.%. All samples demonstrate columnar structures of GaZnO epilayers in scanning transmission electron microscope (STEM) images.

  Preview abstract

We propose a way to take advantage of the mechanical properties of a twodimensional graphene layer to unlock the thickness limitation of particle-shape silver thin
films for near-infrared absorbers.This can be designed by staking graphene and silver thin
film on a substrate through a combination of a graphene transfer method and a magnetron
sputtering technique. We design the stacking of graphene/silver nanoparticle film on a
classical metal-insulator-metal configuration, which consists of a top-layer graphene/silver
nanoparticle layer and a bottom thick silver layer separated by a spacer SiO2 layer. The
experimental analysis of the device points out that nearly 100% absorptance can be achieved
in the near-infrared region.

  Preview abstract