Piezotronics
Piezotronics effect is using the piezoelectric potential (piezopotential) created in materials with piezoelectricity as a “gate” voltage to tune/control the charge carrier transport properties for fabricating new devices. Neil A Downie showed how simple it was to build simple demonstrations on a macro-scale using a sandwich of piezoelectric material and carbon piezoresistive material to make an FET-like amplifying device and put it in a book of science projects for students in 2006. The fundamental principle of piezotronics was introduced by Prof. Zhong Lin Wang at Georgia Institute of Technology in 2007. From 2006, a series of electronic devices have been demonstrated based on this effect, including piezopotential gated field-effect transistor, piezopotential gated diode, strain sensors, force/flow sensors, hybrid field-effect transistor, piezotronic logic gates, electromechanical memories, etc. Piezotronic devices are regarded as a new semiconductor-device category. Piezotronics is likely to have important applications in sensor, human-silicon technology interfacing, MEMS, nanorobotics and active flexible electronics. Mechanism Due to the non-central symmetry in materials such as the wurtzite structured ZnO, GaN and InN, a piezopotential is created in the crystal by applying a stress. Owing to the simultaneous possession of piezoelectricity and semiconductor properties, the piezopotential created in the crystal has a strong