带隙渐变纳米线的制备及其非线性光学效应研究

由于一般的半导体纳米材料只有单一带隙,限制了其应用范围。通过搭建气–液–固法生长纳米线的实验装置,引入金作为催化剂,并加入移动源,成功制备出单根带隙渐变的硫硒化镉纳米线。其成分从一端的纯硫化镉连续过渡到另一端的纯硒化镉,对应的带隙从2.44 e V渐变到1.74 e V。并使用波长为405 nm的激光照射该纳米线,得到它的荧光光谱图来证实其带隙呈渐变状态。利用波长为1 064 nm的激光,将其耦合进单根纳米线中,产生了532 nm的绿色倍频光和双光子荧光,这说明硫硒化镉纳米线具有二阶和三阶的非线性光学效应。

Synthesis of Nanowires with the Tunable Bandgap and Nolinear Optical Effect

A common semiconductor nanomaterial has only a single bandgap, which confines its application. An experimental system was set up to carry out the nanowires growth by the vapor-liquid-solid (VLS) method using Au as a catalyst and furnishing with a moving source, and single CdSSe nanowires with tunable bandgap were synthesized successfully. The composition transits from pure CdS in one end into pure CdSe in the other side, correspondingly the bandgap changes from 2.44 eV to 1.74 eV. A laser of wavelength 405 nm was used to confirm the tunable bandgap of the CdSSe nanowires. Further, a laser of 1 064 nm was coupled into the single nanowire, resulting in producing a green double frequency laser of 532 nm and a two-photon fluorescence, which proves that the CdSSe nanowire has a nolinear optical effect of both second and third harmonic generations.