Herein, AlN growth by metalorganic vapor‐phase epitaxy on hole‐type nanopatterned sapphire substrates is investigated. Cracking occurs for an unexpectedly thin‐layer thickness, which is associated to altered nucleation conditions caused by the sapphire pattern. To overcome the obstacle of cracking and at the same time to decrease the threading disl...
Herein, the scope is to provide an overview on the current status of AlN/sapphire templates for ultraviolet B (UVB) and ultraviolet C (UVC) light‐emitting diodes (LEDs) with focus on the work done previously. Furthermore, approaches to improve the properties of such AlN/sapphire templates by the combination of high‐temperature annealing (HTA) and p...
Published in Journal of physics. Condensed matter : an Institute of Physics journal
We investigated band alignment of non-polar and polar GaN/AlN heterojunction by using density functional theory (DFT) with the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional. In the heterojunction model, AlN was considered as a substrate while strained GaN was grown on top. The deformation potential of GaN, were included to calculate the unstraine...
Ultra wide band gap (UWBG) materials such as AlN are part of a class of materials that have a larger band gap than conventional wide band gap (WBG) materials such as GaN, allowing higher operating voltages. In this work we present the fabrication and DC / high voltage characterizations of AlN/AlGaN/AlN double heterostructure that are regrown by met...
Published in Materials
Recently, heterogeneous structured metals have attracted extensive interest due to their exciting mechanical properties. In this work, an AlN/Al nanocomposite with heterogeneous distribution of AlN nanoparticles was successfully prepared by a liquid-solid reaction method combined with subsequent extrusion deformation, which behaves an excellent syn...
Published in Journal of Superhard Materials
Abstract—The results of studying the structure of materials with maximum hardness and fracture toughness values, which are obtained by hot pressing of mixtures of commercial Cr2O3 micro powders with 15, 25, and 35 wt % AlN, are reported. It is shown that these materials have the dispersed heterophase structure regardless of the composition of the i...
Published in Optics and Spectroscopy
AbstractThe mechanisms of photo- and thermoluminescence processes in cation-deficient submicron AlN crystals after UV excitation are studied. The observed emission spectra represent a superposition of bands peaking at 3.0 and 2.5 eV. These spectral features are related to electronic transitions with participation of ON impurity centers and oxygen–v...
Published in Journal of the Korean Physical Society
A thick AlN epilayer with an approximately 1.25-mm thickness was grown on a sapphire substrate by using a mixed source (Al+Ga of very small amount) at around 1150 °C for 2 hours and a mixed-source hydride vapor phase epitaxy (HVPE) method in a simplified reactor interlinked in series with no separation between the source and the growth zones. The s...
Published in International Journal for Simulation and Multidisciplinary Design Optimization
In this paper, mathematical modeling and simulation of a MEMS-based clamped square-shape membrane for capacitive pressure sensors have been performed. Three types of membrane materials were investigated (i.e. Zinc Oxide (ZnO), Zinc Sulfide (ZnS) and Aluminum Nitride (AlN)). Various performance parameters such as capacitance changes, deflection, non...
Published in Sensors (Basel, Switzerland)
In this work, we present a two-dimensional Finite Element Method (2D-FEM) model implemented on a commercial software, COMSOL Multiphysics, that is used to predict the high temperature behavior of surface acoustic wave sensors based on layered structures. The model was validated by using a comparative study between experimental and simulated results...
