皮秒脉冲超快激光调控SiC发光性质研究

【作者】 王思聪； 季凌飞； 李琳； 吴燕； 蒋毅坚；

【机构】 北京工业大学激光工程研究院； 曼彻斯特大学；

【摘要】 第三代半导体SiC具有宽禁带性质(2.40~3.26 eV),可作为短波长发光材料应用于照明器件,然而SiC的间接带隙严重制约了SiC的发光性能,在室温下SiC的发光偏离近带边发射,并且发光效率受到了限制。针对这一特点,我们首次提出了利用超快激光表面改性方法实现对SiC发光性能的调控。我们根据激光诱导等离子体在空气环境下诱导生成与膨胀运动的性质,研究确定了表面改性过程的产生条件。采用皮秒脉冲超快激光,使用功率密度达0.75TW/cm-2的激光束诱导SiC表面产生激光等离子体,对SiC表面进行发光性能的改性研究。我们针对激光改性层的表面形貌、结晶性质、物质组成及成键状态等性质进行了表征,确定了SiC表面激光改性层是以缺陷态跃迁作为主要发光机理;并根据光谱测试结果给出了一系列相关缺陷的发光带,激发带及荧光寿命的信息。本研究可以为超短脉冲激光在半导体与照明产业中的应用提供新的思路。更多还原

【Abstract】 Silicon carbide（SiC）,one of the third-generation semiconductor material with broad band-gap（2.40³.26 eV）,is promising in application of short-wavelength light-emitting devices.However,the luminescence property and efficiency of SiC is constrained by the indirect band-gap,as the luminescence at room temperature shift away from near band emission.To this end,for the first time we utilized the ultra-fast laser surface processing to modify the luminescence property.Based on the generation and expansion of laser-induced plasma in air ambient,we studied the principle and condition of the laser modification.The picosecond laser was used with the power intensity of 0.75 TW/cm^-2 in this study to induce the modification.The characterizations of surface morphology,crystalline property,elemental component and bonding conditions of the surface layer were conducted,and the luminescence mechanism was established as transition of multiple defect states;based on the photoluminescence（PL） spectra,the emission band,excitation band and fluorescence lifetime was observed.This work may shed light on the fabrication of next generation diode lighting devices with ultra-fast laser.更多还原