  This paper reports a few-layer black phosphorus thickness pattern fabricated
by a top-down nanofabrication approach. This was achieved by a new wet etching
process that can etch selected regions of few-layer black phosphorus with an
atomic layer accuracy. This method is deep-UV and e-beam lithography process
compatible,and is free of oxygen and other common doping sources. It provides a
feasible patterning approach for largescale manufacturing of few-layer BP
materials and devices.
