MoS2 nanoparticle formation in a low pressure environment

Formation of MoS2 nanoparticles at pressures between 0.5 and 10 Torr has been studied. Two different chemistries for the particle nucleation are compared: one based on MoCl5 and H2S, and the other based on MoCl5 and S. In both cases particle formation has been studied in a thermal oven and in a radio-frequency discharge. Typically, the reaction rates at low pressures are too low for an efficient thermal particle production. At pressures below 10 Torr no particle production in the oven is achieved in H2S chemistry. In the more reactive chemistry based on sulfur, the optimal conditions for thermal particle growth are found at 10 Torr and low gas flows, using excess of hydrogen. In the radio-frequency discharge, nanoparticles are readily formed in both chemistries at 0.5 Torr and can be detected in situ by laser light scattering. In the H2S chemistry particles smaller than 100 nm diameter have been synthesized, the sulfur chemistry yields somewhat larger grains. Both in thermal and plasma-enhanced particle syntheses, using excess of hydrogen is beneficial for the stability and purity of the particles

Cytokine secretion in breast cancer cells – MILLIPLEX assay data

© 2019 The Author(s) Metastatic breast cancer is the most advanced stage of breast cancer and the leading cause of breast cancer mortality. Although understanding of the cancer progression and metastasis process has improved, the bi-directional communication between the tumor cell and the tumor microenvironment is still not well understood. Breast cancer cells are highly secretory, and their secretory activity is modulated by a variety of inflammatory stimuli present in the tumor microenvironment. Here, we characterized the cytokine expression in human breast cancer cells (MDA-MB-231, MCF-7, T-47D, and BT-474) in vitro using 41 cytokine MILLIPLEX assay. Further, we compared cytokine expression in breast cancer cells to those in non-tumorigenic human breast epithelial MCF-10A cells

Impact of the substrate and buffer design on the performance of GaN on Si power HEMTs

Abstract This paper presents an extensive analysis of the impact of substrate and buffer properties on the performance and breakdown voltage of E-mode power HEMTs. We investigated the impact of buffer thickness, substrate resistivity and substrate miscut angle, by characterizing several wafers by means of DC and pulsed measurement. The results demonstrate that: (i) the resistivity of the silicon substrate strongly impacts on the breakdown voltage and vertical leakage current. In fact, highly resistive substrates may partly deplete under high vertical bias, thus limiting the total potential drop on the epitaxial layers. As a consequence, the vertical I V plots show a "plateau", that limits the vertical leakage. (ii) the depletion of the substrate may worsen the dynamic performance of the devices, due to an enhancement of buffer trapping. (iii) Larger buffer thickness results in an increased robustness of the vertical stack, due to the thicker insulating region. (iv) the miscut angle (0°, 0.5°, and 1°) can significantly impact on both threshold voltage and the 2DEG density; devices with miscut substrate have higher current density. On the other hand, the dynamic on-resistance variation is comparable in the three cases