Field emission from single and few-layer graphene flakes

We report the observation and characterization of field emission current from individual single- and few-layer graphene flakes laid on a flat SiO2/Si substrate. Measurements were performed in a scanning electron microscope chamber equipped with nanoprobes, used as electrodes to realize local measurements of the field emission current. We achieved field emission currents up to 1 {\mu}A from the flat part of graphene flakes at applied fields of few hundred V/{\mu}m. We found that emission process is stable over a period of several hours and that it is well described by a Fowler-Nordheim model for currents over 5 orders of magnitude

Going Ballistic: Graphene Hot Electron Transistors

This paper reviews the experimental and theoretical state of the art in ballistic hot electron transistors that utilize two-dimensional base contacts made from graphene, i.e. graphene base transistors (GBTs). Early performance predictions that indicated potential for THz operation still hold true today, even with improved models that take non-idealities into account. Experimental results clearly demonstrate the basic functionality, with on/off current switching over several orders of magnitude, but further developments are required to exploit the full potential of the GBT device family. In particular, interfaces between graphene and semiconductors or dielectrics are far from perfect and thus limit experimental device integrity, reliability and performance

Identity Leadership, Employee Burnout and the Mediating Role of Team Identification: Evidence from the Global Identity Leadership Development Project

Do leaders who build a sense of shared social identity in their teams thereby protect them from the adverse effects of workplace stress? This is a question that the present paper explores by testing the hypothesis that identity leadership contributes to stronger team identification among employees and, through this, is associated with reduced burnout. We tested this model with unique datasets from the Global Identity Leadership Development (GILD) project with participants from all inhabited continents. We compared two datasets from 2016/2017 (n = 5290; 20 countries) and 2020/2021 (n = 7294; 28 countries) and found very similar levels of identity leadership, team identification and burnout across the five years. An inspection of the 2020/2021 data at the onset of and later in the COVID-19 pandemic showed stable identity leadership levels and slightly higher levels of both burnout and team identification. Supporting our hypotheses, we found almost identical indirect effects (2016/2017, b = −0.132; 2020/2021, b = −0.133) across the five-year span in both datasets. Using a subset of n = 111 German participants surveyed over two waves, we found the indirect effect confirmed over time with identity leadership (at T1) predicting team identification and, in turn, burnout, three months later. Finally, we explored whether there could be a “too-much-of-a-good-thing” effect for identity leadership. Speaking against this, we found a u-shaped quadratic effect whereby ratings of identity leadership at the upper end of the distribution were related to even stronger team identification and a stronger indirect effect on reduced burnout

The effects of CRF antagonists, antalarmin, CP154,526, LWH234, and R121919, in the forced swim test and on swim-induced increases in adrenocorticotropin in rats

Exposure to extreme stress has been suggested to produce long-term, detrimental alterations in the hypothalamic–pituitary–adrenal (HPA) axis leading to the development of mental disorders such as depression. Therefore, compounds that block the effects of stress hormones were investigated as potential therapeutics for depression.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46365/1/213_2005_Article_2164.pd

(Invited) Initial State of Graphene Growth on Ge(001) Surfaces

Graphene electronics is most likely to complement the mainstream Si technologies instead of replacing them. Large area graphene that can be grown on Cu or on Ni must be subsequently transferred to Si, which is problematical. A process in which graphene grows directly on a Si wafer would thus be welcome; yet SiC formation makes this hardly realizable. Researchers search therefore for growth methods on CMOS-compatible substrates, as Ge/Si(001). We discuss the results of ab initio density functional theory (DFT) calculations for the interaction between carbon and germanium during deposition of C atoms (molecular beam epitaxy, MBE) and of small hydrocarbon molecules (chemical vapor deposition, CVD) on the Ge(001)-p(2×2) surface, during graphene nucleation that follows this deposition, and during the initial stage of graphene growth. The major difference between MBE and CVD process is that liberation of germanium from surface dimers by subsurface diffusion of carbon are suppressed in CVD.</jats:p