Control of microstructures of semiconductor nanocrystals by ion implantation and their application for optical materials

自20世纪90年代初发现多孔硅的可见光致发光以来，镶嵌在SiO_2中的Si纳米晶由于其在室温下强烈的可见光致发光而在Si基光电器件中具有潜在的应用前景，引起了人们极大的兴趣。最近，由于在Si纳米晶体中观察到光放大，对这种材料的关注大大增加。硅纳米晶的制备方法很多，包括离子注入、化学气相沉积、溅射、分子束外延、激光烧蚀等，其中离子注入法是制备硅纳米晶的最有前途的方法之一。该技术的优点在于，通过改变注量和加速能量，可以将给定数量的离子放置在受控的深度和分布处。离子束合成硅纳米晶是一种很有潜力的制备方法。 关于我们 本工作研究了快速热退火增强SiO_2中Si纳米晶光致发光的可能性。用离子注入法制备了不同浓度的SiO_2样品。在注入样品中形成纳米晶体的Si沉淀用常规炉退火发生。硅纳米晶的光致发光强度和发射峰能量依赖于注入离子的注量。此外，在常规炉退火之前，通过快速热退火强烈增强发光强度。然而，发光强度随着常规炉退火之后的快速热退火而降低。结果表明，热处理的顺序是影响发光强度的重要因素。此外，发光峰能量被发现是依赖于，但很少，样品的热历史。根据实验结果，我们讨论了光致发光增强的机理，以及通过离子注入和退火在SiO_2基体中产生的封装Si纳米晶的光致发射机理。少

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 … More 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