氢钝化对低温沉积nc-SiO_x/SiO_2多层薄膜发光特性影响机制研究

Study on the Effect of Hydrogen Passivation on Photoluminescence Properties of Low-temperature Depositied nc-SiO_x/SiO_2 Multilayers

采用等离子体增强化学气相沉积技术实现了nc-SiO_x/SiO_2多层结构薄膜在220℃的低温沉积,并对其450℃N_2+H_2形成气体退火前后的微结构及其发光特性进行了研究。结果表明,直接沉积的纳米硅多层薄膜未观察到较明显的室温发光,而形成气体退火后样品出现峰值位于780 nm附近较强的光致发光,归因于活性氢能有效钝化纳米硅表面悬键,提高了材料的发光强度。结合瞬态发光谱分析,采用量子限制-发光中心模型可以合理解释纳米硅多层结构的发光特性。

Nc-SiO_X/ SiO_2 multilayers were prepared at low temperature around 220 ℃ by plasma enhanced chemical vapor deposition technologies( PECVD). The microstructure and photoluminescence properties of the multilayers were investigated before and after annealed at 450 ℃ with N_2+ H_2 formation gas. The results show that the as-synthesized nc-Si multilayers didn't show obvious photoluminescence properties at room temperature while after annealing a photoluminescence appeared at ~ 780 nm with worth noticing increased intensity in order of magnitude. The enhanced photoluminescence intensity could be attributed to the effective interface passivation with silicon dangling bonds induced by the hydrogen annealing. Combining with the time-resolved photoluminescence measurements,the quantum confinement-luminescence center( QCLC) model can be adopted to interpret the PL results of nc-SiO_x/ SiO_2 multilayers.