This paper discusses examination, focusing on the possibilities available in ALN based learning. ALN is an acronym for asynchronous learning networks and in this research this means a web based learning environment supporting anywhere/anytime learning. The notion of mandatory participation in learning activities is argued to be more viable in ALNs rather than traditional classrooms. Mandatory p...

Wurtzite AlN is widely used for deep ultraviolet optoelectronic devices (DUV), which are generally grown along the [0001]-direction of the wurtzite structure on currently available substrates. However, huge internal electrostatic fields are presented within the material along [0001] axis induced by piezoelectric and spontaneous polarization, which has limited the internal quantum efficiency of ...

The two-dimensional strain distribution in a GaN/AlN quantum-dot QD superlattice is measured from high-resolution transmission electron microscopy images using the geometrical phase analysis. The results are compared to elastic theoretical calculations using a combination of Fourier transform and Green’s function techniques. The GaN/AlN system appears to be a model system for a comparison betwe...

By introducing an aluminization process to achieve nucleation of nanowires (NWs), spontaneous growth of AlN NWs on Si substrates has been realized by plasma-assisted molecular beam epitaxy. The AlN NWs are grown from the nuclei formed by the aluminization process, and the NW density and diameter can be controlled by the aluminization parameters. The influence of growth conditions on the morphol...

Brillouin spectroscopy has been used to study the effect of the deposition temperature on the surface acoustic wave SAW propagation velocity of aluminum nitride AlN films. The results show a dependence of the SAW propagation velocity on the growth temperature of AlN films. The highest value of acoustic velocity was obtained for the film elaborated without heating. Structural characterization of...

(Received 1 August 2012; accepted 10 September 2012; published online 8 October 2012) AlN/nþ-GaN heterostructure samples with AlN barrier layer thickness between 1 nm and 4 nm have been analyzed by electrochemical capacitance-voltage measurements with a semiconductorelectrolyte contact to estimate the surface potential of this heterostructure. The combination of using a semiconductor-electrolyt...

Aluminum nitride, an important member of the group III nitrides with the highest bandgap of about 6.2 eV, has excellent thermal conductivity, good electrical resistance, low dielectric loss, high piezoelectric response, and ideal thermal expansion, matching that of silicon. The interest in field-emission (FE) applications of AlN materials has grown because they exhibit a negative electron affin...

FIn this work, AlN/SiCN composite coatings were deposited by r.f.-reactive sputtering method using a facing target-type sputtering (FTS) apparatus with composite targets consisting of Al plate and SiC chips in a gaseous mixture of Ar and N2, and investigated their mechanical properties and microstructure. The indentation hardness (HIT ) of AlN/SiCN coatings prepared from composite targets consi...

Aluminum nitride (AlN) is a well known wide-band gap semiconductor that has been widely used in fabricating various ultraviolet photo-electronic devices. Herein, we demonstrate that a fiber laser can be achieved in Fe-doped AlN fiber where Fe is the active ion and AlN fiber is used as the gain medium. Fe-doped single crystal AlN fibers with a diameter of 20-50 μm and a length of 0.5-1 mm were p...

We measured the ellipsometric response from 0.7-5.4 eV of c-axis oriented AlN on Si (111) grown by molecular beam epitaxy. We determine the film thicknesses and find that for our AlN the refractive index is about 5-10% lower than in bulk AlN single crystals. Most likely, this discrepancy is due to a low film density (compared to bulk AlN), based on measurements using Rutherford backscattering. ...