Etching mechanism of atomic Al layers during MXene synthesis and Their application to Gas Sensors
발표자
()
초록
내용
Since the first report on MXene, many researches related to synthesis, property enhancement and their applications have been reported, while the basic mechanism regarding the atomic layer etching in MXene synthesis is still unsolved. Here, we visualize the etching behavior of the Ti3AlC2 MAX phase at the atomic scale and correlate the structural changes of the Ti3AlC2 MAX phase as a function of etching time and etchant type for the first time to reveal the etching mechanism. For all etchants, we show that etching starts from the edges and propagates along the basal planes, leading to the stepwise etching of Al layers. However, the etching mechanism for the grain boundary differs substantially depending on the type of etchant. HF and NH4HF2 etchants can break polycrystals at their grain boundaries into single crystals, whereas polycrystals remain after LiF/HCl etching. We also discuss the gas sensor application of the MXene.