This paper presents the work done in designing and fabricating miniaturised inertial measurement units (IMU's) for 2 distinct applications: a 25mm form factor wireless sensor network platform and a novel display interface. The 2 IMU's developed for the novel display interface are a low-dynamics sensor module that includes a 3-axis magnetometer and a 2-axis inclinometer and high-dynamics sensing module, which consists of a complete strapdown inertial measurement system and a compass module. The IMU designed for the wireless sensor network platform is based on the high-dynamics sensing module but realised in a 25mm times 25mm panel. This panel increases the sensory capabilities of each network node allowing the orientation of each node to be completely realized. As part of the NMRC's technology development there is a drive towards wireless nodes for sensor networks of volume in the sub 5mm region. As a stepping stone towards this goal, the target objectives for the development of a 25mm cube module were to develop, a low volume prototyping and experimentation platform. This is for use as a platform for sensing and actuating through various parameters, for use in scalable, reconfigurable distributed autonomous sensing networks in a number of research projects currently underway in the NMRC. This paper outlines the development of the system with particular emphasis on the IMU layer. The total system is packaged in a modular 25mm cubed form factor which gives the capability for the module to be utilised in a wide variety of projects incorporating a multitude of actuators/sensors in miniaturised, mobile, autonomous systems.

This paper summarises the application of the laser-based electro-absorptive technique of photoreflectance (PR) for the study of vertical cavity surface emitting lasers (VCSELs). PR results are shown to reveal the technologically important cavity mode and ground state quantum well exciton structures. AlGaAs/GaAs based quantum well VCSELs were examined with and without top mirror layers as a function of laser pump excitation conditions, with results compared with angle-dependent PR data. Cavity mode and quantum well alignments were also studied with reference to the un-modulated reflectance signal as well as correlated with photoluminescence data. The results demonstrate the importance of PR metrology for state-of-art VCSEL characterisation.

In this paper we study the changes in the microstructural and optical properties of silicon thin films produced by the variation of the parameters (temperature and pressure) of the low-pressure chemical vapour deposition (LPCVD) process. Silicon thin films prepared by LPCVD on oxidized silicon substrates over a large range of process parameters (Tdep=500–615°C, pdep=20–100 Pa) have been characterized by Raman spectroscopy, spectroscopic ellipsometry (SE), X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. The phase transition of as-deposited silicon from an amorphous to a crystalline phase via an intermediate mixed phase (few grains in amorphous silicon matrix) can be monitored by the changes in the optical properties and in the Raman spectra. LPCVD parameters, which control the deposition kinetics, are able to influence the optical properties, the structure and/or morphology of the as-deposited LPCVD silicon films. The SE and Raman results prove that it is possible to grow by LPCVD (from pure silane), a silicon film in a (poly)crystalline state at a temperature as low as 500°C.