Mechanochemical reactions of the GaN-Al_(2)O_(3) interface offer a novel principle for scientific and technological merits in the micro-/nano-scale ultra-precision surface machining.In this work,the mechanochemical re...Mechanochemical reactions of the GaN-Al_(2)O_(3) interface offer a novel principle for scientific and technological merits in the micro-/nano-scale ultra-precision surface machining.In this work,the mechanochemical reactions on Ga-and N-faced GaN surfaces rubbed by the Al_(2)O_(3) nanoasperity as a function of the environmental humidity were investigated.Experimental results indicate that the N-face exhibits much stronger mechanochemical removal over the relative humidity range of 20%-80%than the Ga-face.Increasing water molecules in environmental conditions significantly promotes the interfacial mechanochemical reactions and hence accelerates the atomic attrition on N-face.The hypothesized mechanism of the selective water-involved mechanochemical removal is associated with the dangling bond configuration,which affects the mechanically-stimulated chemical reactions via altering the activation energy barrier to form the bonding bridge across the sliding interface.These findings can enrich the understanding of the underlying mechanism of mechanochemical reactions at GaN-Al_(2)O_(3) interface and a broad cognition for regulating the mechanochemical reactions widely existing in scientific and engineering applications.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.51805240 and 51991373)the Natural Science Foundation of Hunan Province(Grant No.2019JJ50518)The authors are also grateful for the assistance from Shiyanjia Lab(https://www.shiyanjia.com)on XPS analysis.
文摘Mechanochemical reactions of the GaN-Al_(2)O_(3) interface offer a novel principle for scientific and technological merits in the micro-/nano-scale ultra-precision surface machining.In this work,the mechanochemical reactions on Ga-and N-faced GaN surfaces rubbed by the Al_(2)O_(3) nanoasperity as a function of the environmental humidity were investigated.Experimental results indicate that the N-face exhibits much stronger mechanochemical removal over the relative humidity range of 20%-80%than the Ga-face.Increasing water molecules in environmental conditions significantly promotes the interfacial mechanochemical reactions and hence accelerates the atomic attrition on N-face.The hypothesized mechanism of the selective water-involved mechanochemical removal is associated with the dangling bond configuration,which affects the mechanically-stimulated chemical reactions via altering the activation energy barrier to form the bonding bridge across the sliding interface.These findings can enrich the understanding of the underlying mechanism of mechanochemical reactions at GaN-Al_(2)O_(3) interface and a broad cognition for regulating the mechanochemical reactions widely existing in scientific and engineering applications.
