Mid-IR Surface Plasmon Polaritons in CdZnO thin films on GaAs

• Published in: Applied surface science Vol. 608; p. 155060
• Main Authors: Martínez Castellano, Eduardo, Yeste, Javier, Abuin, Manuel, Martínez-Tomás, Maria del Carmen, Klymov, Oleksii, Muñoz-Sanjosé, Vicente, Montes Bajo, Miguel, Hierro, Adrian
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-01-2023
• Subjects: CdO; CdZnO; Grating coupling; Plasmonics; Surface Plasmon Polariton; Surface Plasmon Polariton; Grating coupling; Plasmonics; CdZnO; CdO
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.155060

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•In this work, the first integration of a continuous polycrystalline CdZnO thin layer on GaAs, one of the dominant mid-IR optoelectronic platforms, is reported.•The preserved out-of-plane orientation of the crystal grain yields a very minor degradation of the plasma damping compared to monocrystalline CdZnO grown on sapphire.•The CdZnO/GaAs system holds Surface Plasmon Polaritons with a figure of merit comparable to the best TCOs in the mid-IR: AZO, GZO or ITO.•This work opens the door for the use of plasmonics in the amplification and control of light in CdZnO/GaAs hybrid devices.
Metal-oxides are known to be ideal alternatives to noble metals for mid-IR plasmonics, but they are typically grown on substrates as sapphire or glass, which cannot be used as active materials in electronic devices. We demonstrate here that thin Cd(Zn)O films can be integrated on GaAs, one of the dominant optoelectronic material platforms in the mid-IR. Cd(Zn)O is likely the best plasmonic material in this region of the spectrum, and we show that when deposited on GaAs it yields polycrystalline films that support surface plasmon polaritons (SPPs). As a result of the preserved out-of-plane orientation of the crystal grains, the plasma damping in these layers is very moderately degraded with respect to monocrystalline layers on sapphire, yielding an SPP quality factor comparable to other typical TCOs like AZO, GZO or ITO, but with the added functionality of being integrated on GaAs. Hence, these results open the door for the development of future hybrid Cd(Zn)O/GaAs technology, where Cd(Zn)O can be used to amplify the electric field in underlying devices, e.g. photodetectors.