NOVEL TWO-DIMENSIONAL MATERIALS CAPTURED IN SPACE AND TIME

二维（2D）层状材料因其独特的结构、电子、光子和热性能而备受关注。这种材料最著名的例子很可能是石墨烯，它是由单原子层碳构成的。这种特殊材料的发现开辟了生长和探索其他层状材料家族的可能性。事实上，石墨烯可能只是冰山一角，因为氮化物、二硫化物和氧化物家族的二维材料开始出现。

Two-dimensional (2D) layered materials have attracted much attention due to their unusual structural, electronic, photonic and thermal properties. Quite possible the best known example of such a material is graphene which is made of single atomic layer of carbon. The discovery of this specific material has opened up the possibility of growing and exploring other families of layered materials. In fact, graphene might be just the tip of an iceberg as 2D materials in the nitrides, dichalcogenides and oxides families began to emerge. The overall research goal of this Discovery Project is to explore low-dimensional materials and create new knowledge that is fundamental for our ability to predict, control and design functional properties out of these newly emerging material systems. In particular, it will investigate the thermal and phononic properties of graphene, search for ultrafast metallic-semiconducting switching behavior in molybdenum disulfide, and explore the energy transfer phenomena. For this purpose a fundamentally new experimental paradigm, the ultrafast transmission electron microscopy (UTEM) that is unique in Canada, will be used. In this methodology, the material system is excited with an ultrafast photon pulse and the ensuing dynamics is captured with ultrashort electron bunches, revealing the inner clockwork of the microscopic world. Unlike other approaches, UTEM provides the ability to selectively probe local sites at the nanoscale. Dr. Yurtsever has contributed greatly to the realization of this technology and he will apply this expertise to low-dimensional materials in this proposal. Although the proposed research aims to answer fundamental questions pertaining to 2D materials, it has potential for an impact on the Canadian technological output with far-reaching consequences. To give a few examples, energy transfer between nanostructures, interfaces and nano-contacts are the basis of energy conversion devices. Through experiments such as those proposed in this project, the realization of efficient waste-heat recovery devices and photovoltaics will be possible. Furthermore, the ultrafast plane gliding in molybdenum disulfide, and the resulting electronic-property transition, will pave the way for the next-generation, non-volatile memory chips and electronic components that can operate at the terahertz frequencies. In addition to significant contributions to the related fields, this project also offers unique opportunities to train highly qualified personnel. These contributions will strengthen the Canada’s position in 2D materials, ultrafast imaging technologies and other related industries. Consequently, the project is well aligned with the specific goals of NSERC to advance knowledge in the physical sciences and to provide a platform for intellectual property, thus underpinning future development of commercial ventures within Canada.