AP Distinguished Seminar - Charge Injection and Contact Resistance for 2D Materials Based Devices

Charge (or electron) injection across an interface is a fundamental process in applied physics, which has broad applications in electronics, plasma, beam and others. Depending on the energy used to liberate the electrons, it can be broadly characterised into 3 processes: thermionic emission TE (thermal energy), field emission FE (quantum tunneling), and photoemission PE (photon absorption or optical tunneling). At high current regime, the emission current density will become the space charge limited emission (SCLE). Basic models for these emissions (TE, PE, PE, SCLE) for metals or traditional materials have been widely studied: Richardson law, Fowler-Nordheim (FN) law, Fowler-Dubridge (FD), Keldysh model, and Child-Langmuir (CL) law. With the development of two-dimensional (2D) materials-based electronics, these classical models will require new revision to account for the injection process at the 2D-2D or 2D-3D interfaces. Using these new injection models, contact resistance will be presented for both DC and AC contact. At such small dimension, the effects of roughness cannot be ignored and fractional modeling will be presented to account for such effects. With the advances of few-cycle lasers, the ultrafast laser excitation to produce ultrashort pulses of electrons will be possible for the future of PHz electronics. In this presentation, we will share our findings and recent works by others on these topics.