Title:Piezotronics and Piezo-phototronics of Third Generation Semiconductors

TheorySpeaker:Prof. WANG Zhong Li（Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, China.& School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta USA）

Time: Jul. 12, 2018 3:00PM

Venue:Academic Conference Center, IOS, CAS

Abstract: Piezoelectricity, a phenomenon known for centuries, is an effect that is about the production of electrical potential in a substance as the pressure on it changes. For wurtzite structures such as ZnO, GaN, InN and ZnS, due to the polarization of ions in a crystal that has non-central symmetry, a piezoelectric potential (piezopotential) is created in the crystal by applying a stress owing to the presence of one atomic-layer thick polarization charges at the surface/interface. The effect of piezopotential on the transport behavior of charge carriers is significant in II-VI and III-V compound semiconductors due to their multiple functionalities of piezoelectricity, semiconductor and photon excitation. By utilizing the advantages offered by these properties, a few new fields have been created. Electronics fabricated by using inner-crystal piezopotential as a “gate” voltage to tune/control the charge transport behavior is named piezotronics, with applications in strain/force/pressure triggered/controlled electronic devices, sensors and logic units. Piezo-phototronic effect is a result of three-way coupling among piezoelectricity, photonic excitation and semiconductor transport, which allows tuning and controlling of electro-optical processes by strain induced piezopotential. Lastly, photon emission due to piezoelectric potential is also introduced as a new field of piezophotonics. The objective of this talk is to introduce the fundamentals of piezotronics and piezo-phototronics and to give an updated progress about their applications in human-machine interfacing, optoelectronics, sensors and chemistry (LED, solar cell, photon detectors, photon catalysis). Finally, these effects were also extended to 2D materials such as MoS2.
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