  The surface potential and the efficiency of interfacial charge transfer are
extremely important for designing future semiconductor devices based on the
emerging two-dimensional (2D) phosphorene. Here, we directly measured the
strongly layer-dependent surface potential of mono- and few-layer phosphorene
on gold, which confirms with the reported theoretical prediction. At the same
time, we used an optical way - photoluminescence (PL) spectroscopy to probe the
charge transfer in phosphorene-gold hybrid system. We firstly observed highly
anisotropic and layer-dependent PL quenching in the phosphorene-gold hybrid
system, which is attributed to the highly anisotropic/layer-dependent
interfacial charge transfer.
