Samsung scientists have shown how silica nanowires with improved physical properties can be prepared by adjusting the size, density, crystalline properties and interval of silicon nanodots. The silica nanowires comprising silicon nanodots can be effectively used in a variety of semiconductor devices including CTF memory, image sensors, photodetectors, light emitting diodes, laser diodes, and the other semiconductor devices.
The illustration is a transmission electron microscopic (TEM) image of Samsung’s silica nanowire with metal nanodots
In U.S. Patent Application 20100006820, Samsung Electronics Co., Ltd. (Suwon-si, KR) shares their nanofabrication process for preparing silica nanowire containing silicon nanodots which have superior capacitance characteristics when compared with that of a material used as a capacitor in conventional semiconductors.
In addition, the electron trapping ability of the silicon nanodots is improved, and thus the silica nanowires comprising silicon nanodots are suitable for use in semiconductor devices, for example, bottom-up type cross-track-flash (CTF) memory devices, according to inventors Gyeongsu Park, Eunkyung Lee, Jaehak Lee, Byounglyong Choi, Jaegwan Chung and Sung Heo.
Further, when the silica nanowires comprising silicon nanodots can be used in solar cells. It is easy to adjust the thickness of the nanowires in order to adjust the amount of light and sensitivity. In addition, by the adjusting the size of the silicon nanodots, it is possible to absorb light with infrared ray wavelengths, visible ray wavelengths, and ultraviolet ray wavelengths, and thus the photoelectron generation efficiency can be significantly increased.
Moreover, by varying the size of the silicon nanodots of the silica nanowires, various types of nanowires in which absorption wavelength bands are adjusted can be obtained. When these nanowires are used in image sensors, it is possible to miniaturize the size of red-green-blue ("RGB") plane arrangement pixels and a vertical arrangement of the structure is possible. Thus, image sensors with high sensitivity can be manufactured.
In general, the silica nanowire can be grown through a vapor-liquid-solid ("VLS") process or a solid-liquid-solid ("SLS") process. The method of coating the metal catalyst on the substrate is not particularly limited. Examples of the coating process include CVD, sputtering, e-beam evaporation, vacuum deposition, spin coating, or dipping. The diameter of the silica nanowire varies according to the diameter of the metal catalyst, and thus can be controlled by adjusting the diameter of metal catalyst. The adjustment of the diameter of metal catalyst directly affects the growth of the silica nanowire.
Presently, research into methods of preparing nanoparticles and studying the physical properties of nanoparticles is being actively pursued. However, general methods of manufacturing nanowires that can produce nanowires on commercial scales are not well developed yet.
FIG. 8 is a TEM image of Samsung silica nanowire comprising silicon nanodots
