SYNTHESIS AND CHARACTERIZATION OF NANOCRYSTALLINE SILICON BY ATMOSPHERICS PRESSURE PLASMA JET -ELECTRONIC AND OPTICAL PROPERTIES-

以四氯硅烷、SiCl4和H2为原料，采用射频等离子体增强化学气相沉积的方法，在120℃的热生长的SiO_2衬底上制备了发光的纳米硅点。在可见光区有光致发光，由两个宽带组成，对应的光子能量分别为1.38 eV和1.48 eV。对于直径小于10 nm的点，在空气中存储可以增强光致发光，并使光致发光的峰值能量向更高的波长移动。傅立叶变换衰减全反射吸收光谱(FTIR-ATR)研究表明，在3-5 nm的网点尺寸下，自发氧化70h后达到饱和。氧化过程中光致发光强度、光致发光峰能量蓝移和表面终止物种之间的关系表明，这些变化归因于Si纳米晶点/SiO_2界面上辐射中心密度的增加和量子限制效应的增强。此外，我们还研制了大气压射频微等离子体射流。我们还尝试了用Ar等离子体射流快速重结晶非晶硅。再结晶区也显示出较强的可见光致发光。

Luminescent nanocrystalline silicon dots were fabricated on thermally grown SiO_2 at 120℃ by rf plasma-enhanced chemical vapor deposition using tetrachlorosilane, SiCl_4 and H_2. As-deposited Si dots exhibits photoluminescence (PL) in the visible region, consisting of two broad bands corresponding to photon energies of 1.38 and 1.48 eV. Storage in air enhances PL and shifts the PL peak energy to higher wavelengths for dots of diameter less than 10 nm. Fourier transform attenuated total reflection absorption spectroscopy (FTIR-ATR) study reveals that the spontaneous oxidation proceeds until saturation after 70 h at dot sizes of 3-5 nm. The relationship between PL intensity, blueshift of the PL peak energy, and surface termination species during oxidation indicates that these changes are attributed yo the increased density of radaitive centers at the Si nanocrystal dot/SiO_2 interface and enhancement of quantum confinement effect. In addition, we have developed the rf microplasma jet at atmospheric pressure. We also attempted the quick recrystallization of amorphous silicon using an plasma jet of argon. The recrystallized region also exhibits the strong visible PL.