Top-Gated Chemical Vapor Deposited Mos2 Field-Effect Transistors On Si3N4 Substrates

We report the electrical characteristics of chemical vapor deposited (CVD) monolayer molybdenum disulfide (MoS2) top-gated field-effect transistors (FETs) on silicon nitride (Si3N4) substrates. We show that Si3N4 substrates offer comparable electrical performance to thermally grown SiO2 substrates for MoS2 FETs, offering an attractive passivating substrate for transition-metal dichalcogenides (TMD) with a smooth surface morphology. Single-crystal MoS2 grains are grown via vapor transport process using solid precursors directly on low pressure CVD Si3N4, eliminating the need for transfer processes which degrade electrical performance. Monolayer top-gated MoS2 FETs with Al2O3 gate dielectric on Si3N4 achieve a room temperature mobility of 24 cm(2)/V s with I-on/I-off current ratios exceeding 10(7). Using HfO2 as a gate dielectric, monolayer top-gated CVD MoS2 FETs on Si3N4 achieve current densities of 55 mu A/mu m and a transconductance of 6.12 mu S/mu m at V-tg of -5V and V-ds of 2V. We observe an increase in mobility at lower temperatures, indicating phonon scattering may dominate over charged impurity scattering in our devices. Our results show that Si3N4 is an attractive alternative to thermally grown SiO2 substrate for TMD FETs. (C) 2015 AIP Publishing LLC.STTR programNSF NASCENT ERCArmy Research Office under STTR W911NF-14-P-0030Microelectronics Research Cente

Attitude about mental illness of health care providers and community leaders in rural Haryana, North India

Background: Attitude about mental illness determines health seeking of the people. Success of National Mental Health Programme (NMHP) is dependent on attitude about mental illness of various stakeholders in the programme. Material & Methods: A community based cross-sectional study was carried out in Ballabgarh block of Faridabad district in Haryana. We aimed to study attitude about mental illness of various stakeholders of health care providers (HCP), community leaders in rural area of Haryana, north India. Study area consisting of five Primary Health Centers (PHCs) serving 2,12,000 rural population. All HCP working at PHCs, Accredited Social Health Activist (ASHA) and community leaders in study area were approached for participation. Hindi version of Opinion about Mental illness Scale for Chinese Community (OMICC) was used to study attitude. Results: In total, 467 participants were participated in the study. Of which, HCP, ASHAs and community leaders were 81 (17.4%), 145 (31.0%) and 241 (51.6%) respectively. Community members reported socially restrictive, pessimistic and stereotyping attitude towards mentally ill person. ASHA and HCP reported stereotyping attitude about person with mental illness. None of the stakeholders reported stigmatizing attitude. Conclusion: Training programme focusing on spectrum of mental illness for HCP and ASHA working in rural area under NMHP programme is needed. Awareness generation of community leaders about bio-medical concept of mental illness is cornerstone of NMHP success in India

Stacking Order Driven Optical Properties and Carrier Dynamics in ReS2

Two distinct stacking orders in ReS2 are identified without ambiguity and their influence on vibrational, optical properties and carrier dynamics are investigated. With atomic resolution scanning transmission electron microscopy (STEM), two stacking orders are determined as AA stacking with negligible displacement across layers, and AB stacking with about a one-unit cell displacement along the a axis. First-principle calculations confirm that these two stacking orders correspond to two local energy minima. Raman spectra inform a consistent difference of modes I & III, about 13 cm-1 for AA stacking, and 20 cm-1 for AB stacking, making a simple tool for determining the stacking orders in ReS2. Polarized photoluminescence (PL) reveals that AB stacking possesses blue-shifted PL peak positions, and broader peak widths, compared with AA stacking, indicating stronger interlayer interaction. Transient transmission measured with femtosecond pump probe spectroscopy suggests exciton dynamics being more anisotropic in AB stacking, where excited state absorption related to Exc. III mode disappears when probe polarization aligns perpendicular to b axis. Our findings underscore the stacking-order driven optical properties and carrier dynamics of ReS2, mediate many seemingly contradictory results in literature, and open up an opportunity to engineer electronic devices with new functionalities by manipulating the stacking order