Quantitatively Enhanced Reliability and Uniformity of High-κ Dielectrics on Graphene Enabled by Self-Assembled Seeding Layers

Wafer-scale solution-derived molecular gate dielectrics for low-voltage graphene electronics

Graphene field-effect transistors are integrated with solution-processed multilayer hybrid organic-inorganic self-assembled nanodielectrics (SANDs). The resulting devices exhibit low-operating voltage (2 V), negligible hysteresis, current saturation with intrinsic gain > 1.0 in vacuum (pressure < 2 x 10-5 Torr), and overall improved performance compared to control devices on conventional SiO2 gate dielectrics. Statistical analysis of the field-effect mobility and residual carrier concentration demonstrate high spatial uniformity of the dielectric interfacial properties and graphene transistor …

Achieving Both High Power and Energy Density in Electrochemical Supercapacitors with Nanoporous Graphene Materials

Supercapacitors, based on the fast ion transportation, are specialized to provide high power, long stability, and efficient energy storage with highly porous electrode materials. However, their low energy density and specific capacitance prevent them from many applications that require long duration. Using a scalable nanoporous graphene synthesis method involving a simple annealing process in hydrogen, here we show graphene supercapacitors capable of achieving a high energy density comparable to what Li-ion batteries can offer, but a much higher power density. Ultra-high specific gravimetric a…

Quantum Dot Self-assembly in Growth of Strained-Layer Thin Films: a Kinet ic Monte-Carlo Study

We use Monte-Carlo simulations to study island formation in the growth of thin semiconducting films deposited on lattice-mismatched substrates. It is known that islands nucleate with critical nuclei of about one atom and grow two dimensionally until they reach a critical size s$_c$, when it is favorable for the islands to become three dimensional. We investigate the mechanism for this transition from two-dimensional(2D) to three-dimensional(3D) growth. Atoms at the edge of 2D islands with the critical size s$_{c}$ become mobile as a result of strain and are promoted to the next level. Edge ato…

利用溅射TiN(111)上自组装SiN$_x$斑块实现晶圆尺度GaN纳米线密度调控

Density control of GaN nanowires at the wafer scale using self-assembled SiN$_x$ patches on sputtered TiN(111)

本文提出在溅射TiN(111)上预沉积亚单层SiN$_x$形成自组装斑块作为成核种子，通过改变SiN$_x$量实现晶圆尺度GaN纳米线密度跨三个数量级的均匀调控，并揭示其成核机制与光学特性。

Identifying suitable substrates for high-quality graphene-based heterostructures

We report on a scanning confocal Raman spectroscopy study investigating the strain-uniformity and the overall strain and doping of high-quality chemical vapour deposited (CVD) graphene-based heterostuctures on a large number of different substrate materials, including hexagonal boron nitride (hBN), transition metal dichalcogenides, silicon, different oxides and nitrides, as well as polymers. By applying a hBN-assisted, contamination free, dry transfer process for CVD graphene, high-quality heterostructures with low doping densities and low strain variations are assembled. The Raman spectra of …