Polar Semiconducting Scandium Nitride as an Infrared Plasmon and Phonon–Polaritonic Material
Krishna Chand Maurya, Dheemahi Rao, Shashidhara Acharya, Pavithra Rao, Ashalatha Indiradevi Kamalasanan Pillai, Shankar Kumar Selvaraja, Magnus Garbrecht, Bivas Saha
Abstract
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 × 10 18 to 1.6 × 10 21 cm –3 . Our work enables infrared nanophotonics with an epitaxial group III semiconducting nitride, opening the possibility for practical applications.