Characterization of phase transformation behaviour and microstructural development of electroless Ni-B coating

Phase transformation behaviour of amorphous electroless Ni-B coating with a targeted composition of Ni-6 wt% B is characterized in conjunction with microstructural development and hardness. Microscopic observations of the as-deposited coating display a novel microstructure which is already phase separated at multiple length scales. Spherical colonies of ∼5 μm consist of 2-3 μm nodular regions which are surrounded by ∼2-3 μm region that contains fine bands ranging from 10 to 70 nm in width. The appearance of three crystalline phases in this binary system at different stages of heat treatment and the concomitant variation in hardness are shown to arise from nanoscale fluctuations in the as-deposited boron content from 4 to 8 wt%. High temperature annealing reveals continuous crystallization up to 430 °C, overlapping with the domain of B loss due to diffusion into the substrate. The implications of such a microstructure for optimal heat treatment procedures are discussed.     

Erratum to: Effect of interface on mid-infrared photothermal response of MoS2 thin film grown by pulsed laser deposition

Nano Research - The correspondence author in the original version of this article was unfortunately wrongly written on page 3571 and the first page of the ESM. Instead of Ankur Goswami1, Priyesh...     

Effect of interface on mid-infrared photothermal response of MoS2 thin film grown by pulsed laser deposition

This study reports on the mid-infrared (mid-IR) photothermal response of multilayer MoS2 thin films grown on crystalline (p-type silicon and c-axisoriented single crystal sapphire) and amorphous (Si/SiO2 and Si/SiN) substrates by pulsed laser deposition (PLD).The photothermal response of the MoS2 films is measured as the changes in the resistance of the MoS2 films when irradiated with a mid-IR (7 to 8.2 μm) source.We show that enhancing the temperature coefficient of resistance (TCR) of the MoS2 thin films is possible by controlling the film-substrate interface through a proper choice of substrate and growth conditions.The thin films grown by PLD are characterized using X-ray diffraction,Raman,atomic force microscopy,X-ray photoelectron microscopy,and transmission electron microscopy.The high-resolution transmission electron microscopy (HRTEM) images show that the MoS2 films grow on sapphire substrates in a layer-by-layer manner with misfit dislocations.The layer growth morphology is disrupted when the films are grown on substrates with a diamond cubic structure (e.g.,silicon) because of twin growth formation.The growth morphology on amorphous substrates,such as Si/SiO2 or Si/SiN,is very different.The PLD-grown MoS2 films on silicon show higher TCR (-2.9％ K-1 at 296 K),higher mid-IR sensitivity (△R/R =5.2％),and higher responsivity (8.7 V·W-1) compared to both the PLD-grown films on other substrates and the mechanically exfoliated MoS2 flakes transferred to different substrates.