A simple and efficient technique for fabricating two-dimensional arrays of silicon nanotips by using electron beam
lithography (EBL) and reactive ion etching (RIE) was reported. For the RIE processes, two kind of reactive gases, CHF<sub>3</sub>
and SF<sub>6</sub>, were used as plasma etching source for Si. The experiment results indicate that the reactive ion etching
mechanism is different: the isotropic process for SF<sub>6</sub> and anisotropic for CHF<sub>3</sub>. It is found that the mixed O<sub>2</sub>/SF<sub>6</sub> plasma
etching can improve the properties of profile and surface of Si nanotips. Under the condition of ratio ~15%, the 10 nm
top size of Si nanotips was obtained.
We propose an approach to achieve single layer of Si nanodots arrays on insulating layer by using KrF pulsed excimer
laser irradiation on ultra-thin hydrogenated amorphous silicon films followed by thermal annealing. Under the suitable
fabrication conditions, the area density of formed Si nanostructures can be higher than 10<sup>11</sup>cm<sup>-2</sup> as revealed by AFM
images. The size of formed Si nanodots is 3-4 nm for sample with initial a-Si:H film thickness of 4 nm. Room
temperature visible light emission can be observed from laser irradiated a-Si:H film after thermal annealing. The results
on electron field emission properties were also presented in this paper.
Light emission variated from violet-blue to red-infrared is observed from a-Si:/SiO<sub>2</sub> multilayers during step by step annealing. The peak of photoluminescence (PL) changes in the range between 417nm and 750nm under excitation of 325nm light as a function of annealing temperature, which is strong enough to be observed by naked eyes. Combined with Fourier Transform Infrared (FTIR) measurements, the correlation of the red PL excited by 488nm Ar<sup>+</sup> laser and the structural evolution during the step by step annealing is detailed studied. The origins of different PL bands and the role of hydrogen and oxygen in microstructures of a-Si:/SiO<sub>2</sub> multilayers are discussed