We report in this paper on the study of surface acoustic wave (SAW) resonators based on an AlN/titanium alloy (TC4) structure. The AlN/TC4 structure with different thicknesses of AlN films was simulated, and the acoustic propagating modes were discussed. Based on the simulation results, interdigital transducers with a periodic length of 24 μm were patterned by lift-off photolithography techniqu...

The epitaxial growth of crystalline wurtzite AlN thin films on ~001! Si substrates by plasma-assisted molecular-beam epitaxy is reported. The nucleation and the growth dynamics have been studied in situ by reflection high-energy electron diffraction. Cross-sectional transmission electron microscopy and x-ray diffraction investigations revealed a two-domain film structure (AlN and AlN! with a 30...

Ž . Ž . The growth of cubic aluminum nitride AlN and cubic gallium nitride GaN is studied. The effects of ambient pressure and substrate temperature on the structure of the AlN and GaN films are systematically investigated. It is shown that the films are amorphous when the temperature and the pressure are too low. Cubic AlN is obtained at a temperature of 8008C and a pressure of 0.2 Torr. Cubic...

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...