Polar Semiconducting Scandium Nitride as an Infrared Plasmon and Phonon-Polaritonic Material.

The interaction of light with collective charge oscillations, called plasmon-polariton, and with polar lattice vibrations, called phonon-polariton, are essential for confining light at deep subwavelength dimensions and achieving strong resonances. Traditionally, doped-semiconductors and conducting metal oxides (CMO) are used to achieve plasmon-polaritons in the near-to-mid infrared (IR), while polar dielectrics are utilized for realizing phonon-polaritons in the long-wavelength IR (LWIR) spectral regions. However, demonstrating low-loss plasmon- and phonon-polaritons in one host material will make it attractive for practical applications. Here, we demonstrate high-quality tunable short-wavelength IR (SWIR) plasmon-polariton and LWIR phonon-polariton in complementary metal-oxide-semiconductor compatible group III-V polar semiconducting scandium nitride (ScN) thin films. We achieve both resonances by utilizing n-type (oxygen) and p-type (magnesium) doping in ScN that allows modulation of carrier concentration from 5 × 1018 to 1.6 × 1021 cm-3. Our work enables infrared nanophotonics with an epitaxial group III semiconducting nitride, opening the possibility for practical applications.

A 0.2 V Micro-Electromechanical Switch Enabled by a Phase Transition.

Micro-electromechanical (MEM) switches, with advantages such as quasi-zero leakage current, emerge as attractive candidates for overcoming the physical limits of complementary metal-oxide semiconductor (CMOS) devices. To practically integrate MEM switches into CMOS circuits, two major challenges must be addressed: sub 1 V operating voltage to match the voltage levels in current circuit systems and being able to deliver at least millions of operating cycles. However, existing sub 1 V mechanical switches are mostly subject to significant body bias and/or limited lifetimes, thus failing to meet both limitations simultaneously. Here 0.2 V MEM switching devices with ≳106 safe operating cycles in ambient air are reported, which achieve the lowest operating voltage in mechanical switches without body bias reported to date. The ultralow operating voltage is mainly enabled by the abrupt phase transition of nanolayered vanadium dioxide (VO2 ) slightly above room temperature. The phase-transition MEM switches open possibilities for sub 1 V hybrid integrated devices/circuits/systems, as well as ultralow power consumption sensors for Internet of Things applications.