Bornmann B, Mingels S, Dams F, Prommesberger C, Schreiner R, Lützenkirchen-Hecht D, Müller G
FB C Physics Department, University of Wuppertal, Wuppertal, Germany.
Rev Sci Instrum. 2012 Jan;83(1):013302. doi: 10.1063/1.3673475.
We have constructed a new ultrahigh vacuum apparatus with a triode configuration for the systematic investigation of photo-induced field emission (PFE) from metallic or semiconducting cathodes. These are exposed to electric fields up to 400 MV∕m and laser irradiation by means of hole or mesh gates. Cathodes and gates are in situ exchangeable and adjustable with high precision to ensure a homogeneous extraction of electrons which are partially transmitted to the fixed electron spectrometer. Its hemispherical sector analyzer provides an energy resolution limit of 8 meV. The commissioning of the measurement system has been performed with a tungsten needle. Its temperature showed up in the high-energy tail of the electron spectrum, while its work function was derived from the spectral low-energy part combined with the integral current-voltage curve. First PFE measurements on B-doped Si-tip arrays yielded a small field emission current increase under green laser illumination. A shift and splitting of the energy spectra was observed which revealed different emission regimes as well as the photosensitivity of the cathode due to carrier excitation into the conduction band. For the full exploitation of the PFE system, a tunable laser over a wide eV-range is required.
我们构建了一种新型的超高真空装置，其采用三极管配置，用于系统研究金属或半导体阴极的光致场发射（PFE）。通过孔栅或网状栅极，这些阴极可承受高达400 MV∕m的电场和激光辐照。阴极和栅极可在原位进行高精度的互换和调节，以确保均匀地提取电子，部分电子会传输到固定的电子能谱仪中。其半球形扇形分析仪的能量分辨率极限为8 meV。测量系统已使用钨针进行调试。其温度出现在电子能谱的高能尾部，而其功函数则由光谱的低能部分结合积分电流 - 电压曲线得出。首次对硼掺杂硅尖阵列进行的PFE测量表明，在绿色激光照射下，场发射电流有小幅增加。观察到能谱的偏移和分裂，这揭示了不同的发射机制以及由于载流子激发进入导带而导致的阴极光敏性。为了充分利用PFE系统，需要一个在宽能量范围内可调谐的激光器。
