Kavli Affiliate: Eli Yablonovitch | Summary:Efficient coupling between integrated optical waveguides and optical fibers is essential to the success of integrated photonics. While many solutions exist, perfectly vertical grating couplers which scatter light out of a waveguide in the direction normal to the waveguide’s top surface are an ideal candidate due to their potential to […]
Kavli Affiliate: Eli Yablonovitch | Summary:Thermophotovotaics convert thermal radiation from local heat sources to electricity. A new breakthrough in creating highly efficient thin-film solar cells can potentially enable thermophotovoltaic systems with unprecedented high efficiency. The current 28.8% single-junction solar efficiency record, by Alta Devices, was achieved by recognizing that a good solar cell needs to […]
Kavli Affiliate: Eli Yablonovitch | Summary:Bottom-up synthesized GNRs and GNR heterostructures have promising electronic properties for high performance field effect transistors (FETs) and ultra-low power devices such as tunnelling FETs. However, the short length and wide band gap of these GNRs have prevented the fabrication of devices with the desired performance and switching behaviour. Here, […]
Kavli Affiliate: Omar M. Yaghi | Summary:Over 85% of all chemical industry products are made using catalysts, with the overwhelming majority of these employing heterogeneous catalysts functioning at the gas-solid interface. Consequently, optimizing catalytic reactor design attracts much effort. Such optimization relies on heat transfer and fluid dynamics modeling coupled to surface reaction kinetics. The […]
Kavli Affiliate: Ali Javey | Summary:The epitaxial growth of 111 oriented Au on MoS$_2$ is well documented despite the large lattice mismatch (~8% biaxial strain), and the fact that a Au 001 orientation results in much less elastic strain. An analysis based on density functional and linear elasticity theories reveals that the 111 orientation is […]
Kavli Affiliate: Ali Javey | Summary:Semiconductor heterostructures are the fundamental platform for many important device applications such as lasers, light-emitting diodes, solar cells and high-electron-mobility transistors. Analogous to traditional heterostructures, layered transition metal dichalcogenide (TMDC) heterostructures can be designed and built by assembling individual single-layers into functional multilayer structures, but in principle with atomically sharp […]
Kavli Affiliate: Ali Javey | Summary:The development of low-resistance source/drain contacts to transition metal dichalcogenides (TMDCs) is crucial for the realization of high-performance logic components. In particular, efficient hole contacts are required for the fabrication of p-type transistors with MoS2, a model TMDC. Previous studies have shown that the Fermi level of elemental metals is […]
Kavli Affiliate: Ali Javey | Summary:We report high performance p-type field-effect transistors based on single layered (thickness, ~0.7 nm) WSe2 as the active channel with chemically doped source/drain contacts and high-κ gate dielectrics. The top-gated monolayer transistors exhibit a high effective hole mobility of ~250 cm2/Vs, perfect subthreshold swing of ~60 mV/dec, and ION/IOFF of […]
Kavli Affiliate: Ali Javey | Summary:We investigate the role of quantum confinement on the performance of gas sensors based on two-dimensional InAs membranes. Pd-decorated InAs membranes configured as H2 sensors are shown to exhibit strong thickness dependence, with ~100x enhancement in the sensor response as the thickness is reduced from 48 to 8 nm. Through […]