Kavli Affiliate: Ting Xu | First 5 Authors: Cencheng Shen, Jaewon Chung, Ronak Mehta, Ting Xu, Joshua T. Vogelstein | Summary: Temporal data are increasingly prevalent in modern data science. A fundamental question is whether two time series are related or not. Existing approaches often have limitations, such as relying on parametric assumptions, detecting only […]
Kavli Affiliate: Peidong Yang | First 5 Authors: Connor G. Bischak, Minliang Lai, Dylan Lu, Zhaochuan Fan, Philippe David | Summary: Microscopic pathways of structural phase transitions are difficult to probe because they occur over multiple, disparate time and length scales. Using $in$ $situ$ nanoscale cathodoluminescence microscopy, we visualize the thermally-driven transition to the perovskite […]
Kavli Affiliate: Ali Javey | First 5 Authors: Der-Hsien Lien, Shiekh Zia Uddin, Matthew Yeh, Matin Amani, Hyungjin Kim | Summary: Defects in conventional semiconductors substantially lower the photoluminescence (PL) quantum yield (QY), a key metric of optoelectronic performance that directly dictates the maximum device efficiency. Two-dimensional (2D) transition metal dichalcogenides (TMDCs), such as monolayer […]
Kavli Affiliate: Ali Javey | Summary:Defects in conventional semiconductors substantially lower the photoluminescence (PL) quantum yield (QY), a key metric of optoelectronic performance that directly dictates the maximum device efficiency. Two-dimensional (2D) transition metal dichalcogenides (TMDCs), such as monolayer MoS2, often exhibit low PL QY for as-processed samples, which has typically been attributed to a […]
Kavli Affiliate: Graham Fleming | Summary:We investigate the spatial properties of sources from the GAIA catalogue previously identified as being members of the Taurus star forming region and which appear in the Spitzer catalogue. We study an area of sky of 10×15 deg, centred on Right Ascension (2000.0) = 68.5 deg and Declination (2000.0)= 27.0 […]
Kavli Affiliate: Ali Javey | Summary:Atomically thin semiconductors such as monolayer MoS2 and WS2 exhibit nonlinear exciton-exciton annihilation at notably low excitation densities (below ~10 excitons/um2 in MoS2). Here, we show that the density threshold at which annihilation occurs can be tuned by changing the underlying substrate. When the supporting substrate is changed from SiO2 […]
Kavli Affiliate: Eli Yablonovitch | Summary:Inverse electromagnetic design has emerged as a way of efficiently designing active and passive electromagnetic devices. This maturing strategy involves optimizing the shape or topology of a device in order to improve a figure of merit–a process which is typically performed using some form of steepest descent algorithm. Naturally, this […]
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, […]