A new wet etching method for black phosphorus layer number engineering: Experiment, modeling and DFT simulations

This paper reports the successful atomic layer patterning of 2-dimensional Black Phosphorus (BP) and the simulation of the etching process by Density Functional Theory (DFT) method. The wet etching process can etch selected regions of few-layer black phosphorous with an atomic layer accuracy, which provides a feasible patterning approach for large-scale manufacturing of few-layer BP materials and devices. Absorption energies of iodine atoms/molecules at different location of BP layer edge were also calculated by DFT method, shown a vertical etching direction preference which was important for achieving high quality patterns.