The formation and subsequent growth of crystalline silicon nanoclusters ͑Si-ncs͒ in annealed silicon-rich silicon oxides ͑SRSOs͒ were studied by glancing angle x-ray diffraction. SRSO samples with Si concentrations ͑y͒ of 0.40, 0.42, and 0.45 were grown by inductively coupled plasma-enhanced chemical-vapor deposition ͑PECVD͒. Samples with y = 0.42 grown by electron-cyclotron-resonance PECVD were also studied. Annealing treatments were performed at temperatures ͑T͒ of 900, 1000, and 1100°C for times ͑t͒ between 0.5 and 3 h in flowing Ar. As-grown SRSO films did not present signs of Si clusters ͑amorphous or crystalline͒; however, ͑111͒, ͑220͒, and ͑311͒ Bragg peaks corresponding to c-Si were clearly seen after annealing at 900°C for the y = 0.45 sample, but only barely seen for the y = 0.42 and undetected for the y = 0.40 samples. For T = 1000°C, all studied SRSO samples clearly showed the c-Si diffraction peaks, which became narrower with increasing t and T. From the width of the Si ͑111͒ peaks, the mean size of Si-ncs and their dependence on T and t was determined. Activation energies were deduced from the T dependence by fitting the results to two growth models of Si precipitates in an a-SiO 2 matrix reported in the literature. The activation energies qualitatively agree with values deduced from transmission electron microscopy studies of annealed SRSO reported in the literature. However, they are significantly lower than Si diffusion activation energies available in the literature for SiO 2 with low excess Si. A broad feature is also observed in the x-ray diffractograms for as-grown samples with low y, which shifts to the peak position corresponding to a-SiO 2 with increasing T. This behavior is explained by the formation of a well-defined a-SiO 2 phase with increasing T, where mixed Si-O 4−n Si n ͑n = 1,2,3͒ tetrahedra in the as-grown alloy are gradually converted into Si-O 4 and Si-Si 4 as phase separation of Si and SiO 2 proceeds. From the measured Si ͑111͒ peak positions, small Si-ncs are found to be tensilely strained by as much as ϳ0.8%. This effect becomes insignificant as Si-ncs become larger with increasing y or T.

We describe and characterize a multichannel modular room temperature photoluminescence spectroscopy system. This low cost instrument offers minimization of size and complexity as well as good flexibility and acceptable spectral resolution. The system employs an efficient flexible front end optics and a sensitive spectrometer with a charge-coupled device array detector. The spectrometer has no moving parts and is more robust than a scanning system. The scientific motivation was to enable the photoluminescence study of various silicon photonics structures. Typical applications are presented for SiOx (x<2) films. It is demonstrated that high-quality steady state photoluminescence data with excellent signal to noise enhancement capability can be delivered besides the ability to perform simultaneous multiwavelength measurements in one shot. This instrument is shown to be useful for evaluating semiconductor wafers, including those intended for light emitting structures from silicon-based photonic crystals. The design, construction, calibration, and the unique features of this system are presented, and performance tests of a prototype are discussed.

Thin films of ZnGa2O4:normalMn films have been deposited by radio frequency magnetron sputtering in order to study the effects of annealing temperatures less than 1000°C on the thin-film electroluminescent properties. Energy-dispersive X-ray compositional analysis showed a loss of zinc during sputtering, with the film composition being Zn0.9Mn0.03Ga2O4. All films showed strong (111) and (222) X-ray reflections relative to the power standard. As the annealing temperature was raised, the texture rotated toward that of the powder material. The as-deposited films showed no photoluminescence; however, once annealed at T⩾750°C, a single emission band at 504 nm was observed. Emission wavelength was independent of annealing temperature. The electroluminescent brightness of the devices peaked at an annealing temperature of 900°C. Peak brightness and efficiency were 350 normalcd/m2 and 0.55 lm/W at 60 Hz, and 1500 normalcd/m2 and 0.30 lm/W at 600 Hz. These high brightness values have been attributed to the roughness of the substrates. © 2001 The Electrochemical Society. All rights reserved.

Incorporating cadmium in the sputtering targets used to grow green-emitting zinc gallate doped with manganese is found to provide improvements in crystallinity, photoluminesience (PL), and electroluminescence (EL) performance, while reducing the annealing temperature requirements. It is shown that as-grown thin films do contain cadmium. The cadmium is then lost during thin-film annealing. The effect of cadmium is interpreted as an enhancement in vacancy concentration during the thin-film annealing process, which improves crystallinity, EL, and PL. X-ray diffraction and microscopy results are carefully studied and discussed.

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