Moving the Plasmon of LaB₆ from IR to Near-IR via Eu-Doping

Tracy M Mattox; D Keith Coffman; Inwhan Roh; Christopher Sims; Jeffrey J Urban

doi:10.3390/ma11020226

Moving the Plasmon of LaB₆ from IR to Near-IR via Eu-Doping

Materials (Basel). 2018 Feb 1;11(2):226. doi: 10.3390/ma11020226.

Authors

Tracy M Mattox¹, D Keith Coffman², Inwhan Roh³, Christopher Sims⁴, Jeffrey J Urban⁵

Affiliations

¹ Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Rd., Berkeley, CA 94720, USA. tmmattox@lbl.gov.
² Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Rd., Berkeley, CA 94720, USA. dcoffm5261@gatech.edu.
³ Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Rd., Berkeley, CA 94720, USA. noinhwan@gmail.com.
⁴ Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Rd., Berkeley, CA 94720, USA. christophersims2017@u.northwestern.edu.
⁵ Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Rd., Berkeley, CA 94720, USA. jjurban@lbl.gov.

Abstract

Lanthanum hexaboride (LaB₆) has become a material of intense interest in recent years due to its low work function, thermal stability and intriguing optical properties. LaB₆ is also a semiconductor plasmonic material with the ability to support strong plasmon modes. Some of these modes uniquely stretch into the infrared, allowing the material to absorb around 1000 nm, which is of great interest to the window industry. It is well known that the plasmon of LaB₆ can be tuned by controlling particle size and shape. In this work, we explore the options available to further tune the optical properties by describing how metal vacancies and Eu doping concentrations are additional knobs for tuning the absorbance from the near-IR to far-IR in La_1-xEu_xB₆ (x = 0, 0.2, 0.5, 0.8, and 1.0). We also report that there is a direct correlation between Eu concentration and metal vacancies within the Eu_1-xLa_xB₆.

Keywords: LaB6; doping; hexaboride; lanthanum hexaboride; plasmon.