Guiding and controlling light at nanoscale in field effect transistor

Abstract

Metal–oxide–semiconductor field-effect transistor (MOSFET) and tunnel field-effect transistor (TFET) are proposed to guide and control the light at nanoscale utilizing the hybridization of plasmonic and optical modes. The hybrid plasmonic (HP) mode is confined in the dielectric sandwiched between the metal gate and semiconductor channel, which results from the coupling of surface plasmonic polariton mode at the metal–dielectric interface with the optical mode in the dielectric. Conventional conductivity modulations in the channel through gate and drain–source voltages are utilized to control the guided light. A long propagation length of 74 μm and a very small mode area of λ2/ 96 are reported for field-effect transistor at an operating wavelength of 1550 nm which are useful to realize low loss and compact optoelectronic devices. The charge-carrier dynamics along with the plasma dispersion effect in the silicon channel, through voltages applied on the gate and source–drain, result in the optical phase modulation in MOSFET and TFET. Phase shift of π radian at a length of 1.2 mm and 0.21 mm is obtained in MOSFET and TFET, respectively. The proposed concept has the potential to enable multifunctionality of the mature field effect transistors. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.