| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2003: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Research Abstract |
After the discovery of the visible photoluminescence from porous silicon in the early 1990s, there has been considerable interest in Si nanocrystals embedded in of SiO_2 because of their potential applications toward Si-based optoelectronic devices due to their intense visible photoluminescence at room temperature. Recently, the attention to this material is greatly increased due to the observation of light amplification in Si nanocrystals. Si nanocrystals have been fabricated by a variety of methods and include such techniques as ion implantation, CVD, sputtering, MBE, laser ablation and so on. One of the most promising approaches to producing Si nanocrystals, compatible with conventional microelectronic processing, may be by ion implantation. This technique has the advantage that a given number of ions can be placed at a controlled depth and distribution by changing the fluences and acceleration energies. Ion beam synthesis of Si nanocrystals is a potential candidate for manufacturin
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g stable and pure Si nanocrystals for applications in monolithically integrated Si-based optoelectronic devices.
In this work, potentialities of rapid thermal annealing to enhance the photoluminescence emission of Si nanocrystals in SiO_2 have been investigated. Ion implantation was used to synthesize specimens of SiO_2 containing excess Si with different concentrations. Si precipitation to form nanocrystals in implanted samples takes place with a conventional furnace anneal. The photoluminescence intensity and the peak energy of emission from Si nanocrystals depend on implanted ion fluence. Moreover, the luminescence intensity is strongly enhanced with a rapid thermal anneal prior to a conventional furnace anneal. The luminescence intensity, however, decreases with a rapid thermal anneal following a conventional furnace anneal. It is found that the order of heat treatment is an important factor in intensities of the luminescence. Moreover, the luminescence peak energy is found to be dependent, but a little, on thermal history of specimens. Based on our experimental results, we discussed about the mechanism of an enhancement of the photoluminescence, together with the mechanism of photoemission from encapsulated Si nanocrystals produced in a SiO_2 matrix by ion implantation and annealing. Less
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