Abstract: Quaternary InxAlyGa1-x-yN semiconductors have
attracted much research interest because the use of this quaternary
offer the great flexibility in tailoring their band gap profile while
maintaining their lattice-matching and structural integrity. The
structural and optical properties of InxAlyGa1-x-yN alloys grown by
molecular beam epitaxy (MBE) is presented. The structural quality of
InxAlyGa1-x-yN layers was characterized using high-resolution X-ray
diffraction (HRXRD). The results confirm that the InxAlyGa1-x-yN
films had wurtzite structure and without phase separation. As the In
composition increases, the Bragg angle of the (0002) InxAlyGa1-x-yN
peak gradually decreases, indicating the increase in the lattice constant
c of the alloys. FWHM of (0002) InxAlyGa1-x-yN decreases with
increasing In composition from 0 to 0.04, that could indicate the
decrease of quality of the samples due to point defects leading to
non-uniformity of the epilayers. UV-VIS spectroscopy have been used
to study the energy band gap of InxAlyGa1-x-yN. As the indium (In)
compositions increases, the energy band gap decreases. However, for
InxAlyGa1-x-yN with In composition of 0.1, the band gap shows a
sudden increase in energy. This is probably due to local alloy
compositional fluctuations in the epilayer. The bowing parameter
which appears also to be very sensitive on In content is investigated
and obtained b = 50.08 for quaternary InxAlyGa1-x-yN alloys. From
photoluminescence (PL) measurement, green luminescence (GL)
appears at PL spectrum of InxAlyGa1-x-yN, emitted for all x at ~530 nm
and it become more pronounced as the In composition (x) increased,
which is believed cause by gallium vacancies and related to isolated
native defects.
Abstract: This work deals with the design of the robotic assembly
system for the roller clamps. The task is characterized by high speed,
high yield and safety engagement. This paper describes the design of
different parts of an automated high speed machine to assemble the
parts of roller clamps. The roller clamp robotic assembly system
performs various processes in the assembly line which include clamp
body and roller feeding, inserting the roller into the clamp body, and
dividing the rejected clamp and successfully assembled clamp into
their own tray. The electrical/electronics design of the machine is
discussed. The target is to design a cost effective, minimum
maintenance and high speed machine for the industry applications.
Abstract: III-nitride quaternary InxAlyGa1-x-yN alloys have experienced considerable interest as potential materials for optoelectronic applications. Despite these interesting applications and the extensive efforts to understand their fundamental properties, research on its fundamental surface property, i.e., surface phonon polariton (SPP) has not yet been reported. In fact, the SPP properties have been shown to provide application for some photonic devices. Hence, there is an absolute need for thorough studies on the SPP properties of this material. In this work, theoretical study on the SPP modes in InAlGaN quaternary alloys are reported. Attention is focus on the wurtzite (α-) structure InxAlyGa1-x-yN semi-crystal with different In composition, x ranging from 0 to 0.10 and constant Al composition, y = 0.06. The SPP modes are obtained through the theoretical simulation by means of anisotropy model. The characteristics of SP dispersion curves are discussed. Accessible results in terms of the experimental point of view are also given. Finally, the results revealed that the SPP mode of α-InxAlyGa1-x-yN semiconductors exhibits two-mode behavior.