405 research outputs found
Electromechanical wavelength tuning of double-membrane photonic crystal cavities
We present a method for tuning the resonant wavelength of photonic crystal
cavities (PCCs) around 1.55 um. Large tuning of the PCC mode is enabled by
electromechanically controlling the separation between two parallel InGaAsP
membranes. A fabrication method to avoid sticking between the membranes is
discussed. Reversible red/blue shifting of the symmetric/anti-symmetric modes
has been observed, which provides clear evidence of the electromechanical
tuning, and a maximum shift of 10 nm with < 6 V applied bias has been obtained.Comment: 9 pages, 3 figure
Size dependent exciton g-factor in self-assembled InAs/InP quantum dots
We have studied the size dependence of the exciton g-factor in self-assembled
InAs/InP quantum dots. Photoluminescence measurements on a large ensemble of
these dots indicate a multimodal height distribution. Cross-sectional Scanning
Tunneling Microscopy measurements have been performed and support the
interpretation of the macro photoluminescence spectra. More than 160 individual
quantum dots have systematically been investigated by analyzing single dot
magneto-luminescence between 1200nm and 1600 nm. We demonstrate a strong
dependence of the exciton g-factor on the height and diameter of the quantum
dots, which eventually gives rise to a sign change of the g-factor. The
observed correlation between exciton g-factor and the size of the dots is in
good agreement with calculations. Moreover, we find a size dependent anisotropy
splitting of the exciton emission in zero magnetic field.Comment: 15 pages, 7 figure
The influence of human resource practices on perceived work ability and the preferred retirement age: A latent growth modelling approach
Organisations are challenged to extend working lives of older workers. However, there is little empirical evidence available on how organisations should do this. This study aims to fill this gap by testing the effect of Human Resource (HR) practices on perceived work ability and the preferred retirement age. Based on the Conversation of Resources theory, we expected that the use of HR practices has a positive effect on perceived work ability and preferred retirement age. We have conducted latent growth curve modelling to test our hypotheses amongst 12,444 employees aged 45 and older at four time points. The results indicate that developmental practices are positively related to work ability, whereas maintenance practices are negatively related to work ability and the preferred retirement age. Accommodative practices are negatively related to the intercepts of both outcomes but not to the slopes, whereas utilisation practices are not related to the outcomes at all.publishedVersio
A linear AC trap for polar molecules in their ground state
Contains fulltext :
98810.pdf (preprint version ) (Open Access
An atomic scale study of Si-doped AlAs by cross-sectional scanning tunneling microscopy and density functional theory
Silicon (Si) donors in GaAs have been the topic of extensive studies since Si
is the most common and well understood n-type dopant in III-V semiconductor
devices and substrates. The indirect bandgap of AlAs compared to the direct one
of GaAs leads to interesting effects when introducing Si dopants. Here we
present a study of cross-sectional scanning tunneling microscopy (X-STM) and
density functional theory (DFT) calculations to study Si donors in AlAs at the
atomic scale. Based on their crystal symmetry and contrast strengths, we
identify Si donors up to four layers below the (110) surface of AlAs.
Interestingly, their short-range local density of states (LDOS) is very similar
to Si atoms in the (110) surface of GaAs. Additionally we show high-resolution
images of Si donors in all these layers. For empty state imaging, the
experimental and simulated STM images based on DFT show excellent agreement for
Si donor up to two layers below the surface
- …