脉冲激光辐照单晶硅形成的低维结构及其光致荧光特性
Hole-net structure and photoluminescence emission monocrystalline on silicon irradiated by laser
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摘要: 将功率密度约为0.5 J·s-1·cm-2、脉冲宽度约为8 ns、束斑直径为0.045 mm、波长为1 064 nm的YAG激光束照射在硅样品表面打出小孔，在孔内的侧壁上形成较规则的网孔状结构；该结构有很强的光致荧光，其强度比该样品的瑞利散射强；发光峰中心约在700 nm处。在无氧化的环境里用激光加工出的硅样品几乎无发光，这证实了氧在光致荧光增强上起着重要作用。用冷等离子体波模型来解释孔侧壁网孔状结构形成的机理,并用量子受限-发光中心模型来解释纳米网孔壁结构的强荧光效应。当激光辐照时间为9 s时，孔洞侧壁上的网孔状结构较稳定,且有较强的光致荧光。Abstract: A kind of hole-net structure can be formed on silicon sample irradiated by pulse laser with power of 0.5 J·s-1·cm-2 and wavelength of 1 064 nm. The photoluminescence(PL) emission is enhanced by the hole-net structure. The PL peak center is about 700 nm. The oxidation-free silicon sample almost does not emit, which proves that oxidation of silicon may be most important in enhancing PL emission. The quantum confinement-luminescence center model is used to explain the increasing PL emission in the hole-net structure. The plasma wave model is used to explain the forming mechanism of hole-net structure. Under the optimum conditions in preparing process, the sample with enhanced PL emission and more stable low-dimensional structures can be obtained by 9 s irradiation.
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Key words:
- laser irradiation /
- hole-net structure /
- photoluminescence enhancement /
- oxidation
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