制备方法对锌掺杂多孔硅蓝光发射强度及稳定性的影响

The influence of different fabricating methods on intensity and stability of blue light emission of zinc-doped porous silicon

分别采用浸渍法和电镀法对多孔硅薄膜进行了锌掺杂。用扫描探针显微镜研究了多孔硅掺杂前后的表面形貌,用荧光分光光度计分析了样品的光致发光特性,发现锌掺杂增强了多孔硅的蓝光发射,且在420nm附近出现了一个小峰,样品放置一个月后,发光强度和峰位变化很小。红外吸收谱表明锌掺杂后,Si—O—Si键、Si2O—SiH键、H2Si—O2键的振动增强,且引入了Zn—O键。锌掺杂多孔硅发射蓝光是由于掺杂后多孔硅无定形程度增大,应力增大,表面进一步被氧化,使纳米硅粒中激发的电子-空穴对在SiOx层中或纳米硅粒与SiOx层界面的发光中心复合发光造成的,420nm处的发光峰是由锌填隙引起浅施主能级上的电子到价带跃迁造成的,同时分析了电镀法掺杂锌的优越性。

Zinc ions were embedded into porous silicon films by immersing and electroplating. Scanning probe microscope was used to characterize the surface morphology of films. Fluorescence photo-spectrometer was used to research the photoluminescence properties of the samples. The blue emission of porous silicon was enhanced after zinc ions＇ doping, there was a small peak near 420nm. A month later, PL intensity and position changed a little. The FTIR showed that the Si-O-Si, Si2O-SiH, H2Si-O2 absorption peaks enhanced, and Zn--O bonds was introduced. The blue light emission enhancement was associated with a more amorphous structure and higher strain in the films and also a higher level of oxidation, the excitation mainly occurred inside the silicon nanoparticles in porous silicon, however, the emission occurred in the luminescence centers in SiOx layers covering silicon nanoparticles. The peak located at 420nm originated from Zinc interstitial defects. The superiority of electroplating was analysed.