Surface Physics Division, Saha Institute of Nuclear Physics, Kolkata, India.
J Phys Condens Matter. 2012 Aug 1;24(30):305502. doi: 10.1088/0953-8984/24/30/305502. Epub 2012 Jul 4.
We study the observed inhomogeneous band bending effects on cleaved MoS(2)(0001) single-crystal surfaces. Both Mo 3d and S 2p core levels were found to shift to lower binding energy in regions of the MoS(2) crystal with high step densities, as suggested by spot splitting of the LEED (low energy electron diffraction) pattern. Surface electronic band structure measurements also reveal a rigid shift of the valence bands in these regions, resulting from local Fermi level pinning effects. A surface electric field gradient on the MoS(2) crystals caused by the charged dislocations from the regions of high step densities generated by the cleaving process is found to explain most of the experimental observations.
我们研究了在劈开的 MoS(2)(0001)单晶表面观察到的非均匀带弯曲效应。正如 LEED（低能电子衍射）图案的斑点分裂所表明的那样，在具有高密度台阶的 MoS(2)晶体区域中，Mo 3d 和 S 2p 芯能级都被发现向较低的结合能移动。表面电子能带结构测量也揭示了这些区域中价带的刚性移动，这是由于局部费米能级钉扎效应。在劈开过程中由高密度台阶区域产生的带电位错引起的 MoS(2)晶体的表面电场梯度被发现可以解释大部分实验观察结果。
