纳米硅量子点/氮化硅三明治结构的电致发光

采用等离子体化学气相沉积技术制备了两种不同非晶硅层厚度的氮化硅/氢化非晶硅/氮化硅三明治结构,研究了不同能量激光退火对薄膜晶化的影响。通过拉曼分析,发现在激光能量为320mJ时,样品开始晶化,随着能量的提高晶化程度增加,在340mJ时达到最大。根据拉曼晶化峰的偏移,计算得出硅量子点尺寸为2.8nm和4.7nm,表明三明治结构对形成的硅量子点的尺寸具有限制作用。设计并制备了基于该结构的电致发光器件,在偏压大于10V时,在室温下可观测到电致发光。发现不同激光能量下晶化后的样品的电致发光强度不同,发光峰位在680nm和720nm附近。分析表明电致发光来源可以归结为电子空穴对在硅量子点中的辐射复合发光。

Electroluminescence from Amorphous SiN/Si Quantum Dots/Amorphous SiN Sandwiched Structures

Amorphous SiN/amorphous Si/amorphous SiN sandwiched structures with two different thicknesses of amorphous Si are prepared by plasma-enhanced chemical vapor deposition. Raman spectra demonstrate the formation of Si quantum dots (QDs) when the laser energy is above 320 mJ and the sizes can be controlled as small as 2.8 nm and 4.7 nm, which suggests that the size-controllable Si QDs can be formed due to constrained confined effect in sandwiched structures. Room temperature electroluminescence (EL) can be detected when the applied voltage is above 10 V, and the intensity varies under different laser energies. The EL spectrum peaks are at 680 nm (2.8 nm QDs) and 720 nm (4.7 nm QDs) which are attributed to the radiative recombination of injected electrons and holes within the Si QDs.