纳秒脉冲激光制备黑硅及其光学性能的研究

Preparation of black silicon by nanosecond pulsed laser and its optical properties

利用纳秒脉冲激光器在常温常压室内环境下扫描刻蚀单晶硅片,通过改变扫描方式和扫描的线间距制备了各种不同结构的黑硅样品,重点研究了扫描方式、扫描间隔、高温吹氧退火时间等对黑硅光致发光(PL)特性的影响,以及不同参量制备的硅表面微结构对光吸收率的影响。利用透射电子显微镜、扫描电子显微镜、光学显微镜、拉曼和荧光光谱仪、吸收光谱仪等对制备的黑硅样品形貌、光吸收和PL发光特性进行了检测与表征,获得了吸收率高于90%且具有良好发光性能的黑硅结构样品。研究发现,采用线性扫描方式制备的黑硅样品的PL光谱主要分布在红光波段,而采用正交扫描方式制备的黑硅样品的PL光谱中在近红外900 nm附近有稳定的发光峰;此外,在黑硅样品中还观察到630 nm附近的电子局域态发光,并通过建立对应的物理模型解释了其发光机理。

A nanosecond pulse laser was used to scan and etch single crystal silicon in room temperature and atmospheric pressure environment in this work,and various black silicon samples with different structure were prepared by changing the scanning mode and scanning line spacing.Then the effects of scanning mode,scanning interval and high temperature oxygen blowing annealing time on the photoluminescence(PL)properties of black silicon were studied,as well as the effect of different microstructure of silicon surface on light absorption rate.The morphology,light absorption and PL characteristics of the prepared black silicon samples were detected and characterized using transmission electron microscopy,scanning electron microscopy,optical microscopy,Raman and fluorescence spectroscopy,absorption spectroscopy,etc.,and black silicon structure samples with an absorption rate higher than 90%were obtained.It is found that the PL spectrum of black silicon samples prepared by linear scanning is mainly distributed in the red band,while the PL spectrum of black silicon samples prepared by orthogonal scanning has a stable emission peak near 900 nm.In addition,the eletron localized luminescence near 630 nm was observed on the black silicon sample,and its luminescence mechanism was explained by establishing a corresponding physical model.