Session Index

In this talk, we will demonstrate novel optoelectronics realized by using band-engineered vdW heterostructures. Specifically, we will show BP-based mid-infrared light emitting diodes and photodetectors that could exhibit excellent optoelectronic properties, including linear-dichroic photoresponses, high speed, high quantum efficiency and long-term stability at room temperature. Via leveraging the integrability of vdW heterostructures, we further show that our developed mid-infrared devices can be readily coupled with mid-infrared SOI waveguides for on-chip sensing and light emissions. Additionally, we will present novel magneto-optoelectronics, accomplished by integrating emerging vdW magnets with monolayer TMDs, and discuss their future potential applications.

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Tri-layer molybdenum disulfide (MoS2) is fabricated into top-gate transistors for memory device applications. By using the atomic layer etching technique before the source/drain formation, one and two isolated MoS2 layers are fabricated on top of two and one layers of MoS2 channels. Due to the van der Waals attachment instead of chemical bonds between MoS2 layers, a long retention time of electrons stored at the isolated MoS2 layers are observed for the devices. The observation of charge storage in thin 2D material layers will be advantageous for the development of memory devices with reduced linewidths.

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In this work, Landau levels with the same energy spacing but different topological
numbers are produced by chiral strain-engineering. Moreover, topological edge states are
formed by combining two patterns with opposite synthetic gauge fields. By tuning the gauge
fields, topological edge states with ultra-short localization lengths can be constructed.

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In this work, single crystals of SnS1-xSex series (x=0;0.2;0.4;0.5;0.6;0.8;1) have been grown by CVT. From analyzing XRD and HRTEM, SnS1-xSex are crystallized in the orthorhombic structure. Angular-dependent polarized Raman shows noticeable change depending on polarization angle, verifying their in-plane anisotropy behavior. The bandgap transition has been obtained from polarized-thermoreflectance, which varies from 0.94 eV (SnSe) to 1.23 eV (SnS) with absorption ~107. Hall-effect and thermoelectric measurements revealed SnS1-xSex are p-type semiconductors with carrier densities larger than 1017 cm−3. SnSe achieved the highest ZT with ZT 0.086. These findings represent that SnS1-xSex suitable for nanoelectronic and nanophotonic devices in near future.

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Evaluating the manufacturing process using ultrasonic waves is an advanced non-destructive inspection technique. Aluminum is the most abundant metallic element on earth and widely used in integrated circuits. We studied the physical mechanism of optically detecting and generating picosecond ultrasonic pulses in aluminum nanofilm, and compared the changes in the detection region under the influence of the surface plasmon effect.

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We investigate the chirality of meta-GMR composed of rotated nanofin on planar waveguide. The characteristic of GMR is that it will resonate within the waveguide structure and generate diffraction within the structure in a specific wavelength. In this study, we change the period, angle, thickness, and incident light source of nanofin to explore the characteristics of various aspects, and found that the resonance peaks of the left and right circularly polarized light are different under the specific period and thickness of nanofin. In our simulation, the circular dichroism (CD) is 0.7.

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A liquid refractive index (RI) sensor was realized using period-chirped guided mode resonance (PC-GMR) filter defined by laser interference lithography. As-realized PC-GMR-based liquid RI sensor demonstrates a detection limit of 1.54x10^(-3) RIU/pixel and corresponding 9032.26 µm/RIU.

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