硅基硒纳米颗粒的发光特性研究

Photoluminescence properties of selenium nanocrystals on Si(100) substrate formed by rapid thermal annealing

由于尺寸缩小引起的量子效应,硒(Se)材料的低维纳米结构具有更高的光响应和低的阈值激射等特性,因此成为纳米电子与纳米光电子器件领域一个重要的研究方向.本文通过对非晶硒薄膜的快速热退火来制备硒纳米颗粒,退火温度在100—180 C之间时,结晶后的硒纳米颗粒均为三角晶体结构,其颗粒尺寸随退火温度的增加而线性增大.光致发光谱测试发现三个发光峰,分别位于1.4 eV,1.7 eV和1.83 eV.研究发现位于1.4 eV处的发光峰来源于非晶硒缺陷发光,位于1.83 eV处的发光峰来源于晶体硒的带带跃迁发光;而位于1.7 eV处的发光峰强度随激发功率增强而指数增大,且向短波长移动,该发光峰应该来源于非晶硒与硒纳米颗粒界面处的施主-受主对复合发光.

We have investigated the structure and photoluminescence （PL） properties of Se nanocrystals （NCs） obtained by rapid thermal annealing of a-Se films on Si substrate. The size ofSe NCs in a trigonal phase increases linearly with increasing temperature. Moreover, three PL peaks located at 1.4, 1.7 and 1.83 eV are observed, which are attributed to the emission of defects in amorphous Se, donor- acceprter pair （DAP） recombination at the interface of amorphous Se and Se NCs, and interband transition of Se crystals, respectively.