Local spectroscopy by spectrally resolved photon mapping of STM induced luminescnce from nanometer-size particles

1.利用扫描隧道显微镜（STM）对石墨表面纳米金颗粒的隧道诱导发光进行了光谱成像测量。利用增强型CCD探测器和光谱仪，在测量STM形貌像的同时记录了发光光谱。基于这些测量，获得了各个光谱带的光谱分辨光子强度图像。将这些光子强度图像与形貌图像进行比较。我们已经观察到两种类型的光谱相关的光子图像。一个与较短波长（~ 650 nm）模式相关联，另一个与较长波长（~ 700 nm）模式相关联。较短波长（~ 650 nm）的光子图与晶粒形貌相关.我们观察到STM在液-固界面上诱导的光子发射。在具有宽电位窗口的非水溶液中进行了STM诱导发光的测量。当STM偏压为4.5V时，在不同的液体中，只有1-4-二氧六环的发光可以被记录。结果表明，与超高真空和空气中的光谱相比，液体中的光谱向长波方向移动。这一结果表明，移位是由隧穿间隙中的介电介质的存在引起的，并且尖端和样品之间的介质的介电常数的增加引起发射光谱的红移。我们计算了在STM的隧道隙中作为介电常数参量的STM诱导光子发射谱，计算表明发射谱的峰向长边移动

1. We have carried out the spectral mapping measurements of tunneling induced luminescence in scanning tunneling microscopy(STM) of nanoscale gold metal particles on the graphite surface. The luminescence spectra are recorded simultaneously with the measurement of STM topography image by using an intensified CCD detector and a spectrograph. Based on the measurements, spectrally resolved photon intensity images are obtained for various spectral bands. Those photon intensity images are compared with the topography image. We have observed two types of spectrally dependent photon images. One is associated with a shorter wavelength (-650 nm) mode and the other a longer wavelength (-700 nm) mode. The photon map of shorter wavelength (-650 nm) is correlated with grain morphology.2. We have observed STM-induced photon emission at liquid-solid interface. The measurement of STM induced luminescence are made in non-aqueous liquid which has a wide potential window. The luminescence can be recorded only for 1-4 dioxane at the STM bias voltage at 4.5 V while various liquid has been tried. The result shows that the spectrum obtained in the liquid is shifted toward longer wavelength compared with that in UHV and air. This result suggests that the shift is caused by the existence of a dielectric medium in the tunneling gap, and that the increase in dielectric constant of a medium between tip and sample causes a red shift of the emission spectra. We have calculated the spectra of the STM-induced photon emission as a parameter of dielectric constant of dielectric media in the tunneling gap of STM.The calculation shows that the peak of the emission spectrum shifts to a longer