Showing papers on "Vertical mobility published in 2018"
TL;DR: The vertical mobility in VFET can be improved by suppressing the trap states by raising the Fermi level of WSe2 and increasing the injected carrier density by applying a high drain voltage, and the mobility in Mn vdWH at +50 V gate voltage is about 76 times higher than the initial mobility of Au vd WH.
Abstract: Vertical integration of 2D layered materials to form van der Waals heterostructures (vdWHs) offers new functional electronic and optoelectronic devices. However, the mobility in vertical carrier transport in vdWHs of vertical field-effect transistor (VFET) is not yet investigated in spite of the importance of mobility for the successful application of VFETs in integrated circuits. Here, the mobility in VFET of vdWHs under different drain biases, gate biases, and metal work functions is first investigated and engineered. The traps in WSe2 are the main source of scattering, which influences the vertical mobility and three distinct transport mechanisms: Ohmic transport, trap-limited transport, and space-charge-limited transport. The vertical mobility in VFET can be improved by suppressing the trap states by raising the Fermi level of WSe2 . This is achieved by increasing the injected carrier density by applying a high drain voltage, or decreasing the Schottky barrier at the graphene/WSe2 and metal/WSe2 junctions by applying a gate bias and reducing the metal work function, respectively. Consequently, the mobility in Mn vdWH at +50 V gate voltage is about 76 times higher than the initial mobility of Au vdWH. This work enables further improvements in the VFET for successful application in integrated circuits.
45 citations
28 Dec 2018
TL;DR: In this article, the authors investigated energy use due to vertical mobility in the context of Asia's diverging cities and proposed a methodology to calculate energy consumption of lifts, based on a detailed review of literature, codes of practice, and 3D city models.
Abstract: Sustainable development of cities and the overall efficiency of urban infrastructure have emerged as central issues in policy consideration. Consequently, investigating the influence of urban physical form on resource use is critical. This paper investigates energy use due to vertical mobility in the context of Asia’s diverging cities. Micro mobility of citizens’ movement in the vertical direction has a distinct impact on the total energy consumption of a city or urban block. The objective of this research is to analyse the impact of different urban morphologies on vertical mobility—from buildings to urban blocks. A methodology is proposed to calculate energy consumption of lifts, based on a detailed review of literature, codes of practice, the International Organisation for Standardisation (ISO)/DIS 25745-1 standard and 3D city models. Furthermore, a tool is developed and applied in 20 typical urban blocks in four cities: Kuwait, Abu Dhabi, Hong Kong and Singapore. The average annual specific energy consumption of lifts varies significantly across the samples. A comparative analysis of all the morphologies across these cities help to understand the impact of building forms, usage, and a number of further parameters on the energy consumption for vertical mobility.
9 citations