University of Tsukuba, Tsukuba 305-8571, Japan.
Nanoscale. 2013 Oct 7;5(19):9170-5. doi: 10.1039/c3nr02433d. Epub 2013 Aug 8.
The tangled mechanism that produces optical pump-probe scanning tunneling microscopy spectra from semiconductors was analyzed by comparing model simulation data with experimental data. The nonlinearities reflected in the spectra, namely, the excitations generated by paired laser pulses with a delay time, the logarithmic relationship between carrier density and surface photovoltage (SPV), and the effect of the change in tunneling barrier height depending on SPV, were examined along with the delay-time-dependent integration process used in measurement. The optimum conditions required to realize reliable measurement, as well as the validity of the microscopy technique, were demonstrated for the first time.
通过将模型模拟数据与实验数据进行比较，分析了产生半导体光泵探针扫描隧道显微镜光谱的复杂机制。光谱中反映的非线性，即由具有延迟时间的成对激光脉冲产生的激发、载流子密度与表面光电压 (SPV) 之间的对数关系，以及隧道势垒高度随 SPV 变化的影响，以及测量中使用的延迟时间相关积分过程进行了检验。首次证明了实现可靠测量所需的最佳条件以及显微镜技术的有效性。
