TY - JOUR
T1 - Unprecedented Thermal Stability of Plasmonic Titanium Nitride Films up to 1400 °C
AU - Krekeler, Tobias
AU - Rout, Surya S.
AU - Krishnamurthy, Gnanavel V.
AU - Störmer, Michael
AU - Arya, Mahima
AU - Ganguly, Ankita
AU - Sutherland, Duncan S.
AU - Bozhevolnyi, Sergey I.
AU - Ritter, Martin
AU - Pedersen, Kjeld
AU - Petrov, Alexander Yu
AU - Eich, Manfred
AU - Chirumamilla, Manohar
N1 - Publisher Copyright:
© 2021 The Authors. Advanced Optical Materials published by Wiley-VCH GmbH
PY - 2021/8
Y1 - 2021/8
N2 - Titanium nitride (TiN) has emerged as one of the most promising refractory materials for plasmonic and photonic applications at high temperatures due to its prominent optical properties along with mechanical and thermal stability. From a high temperature standpoint, TiN is a substitution for Au and Ag in the visible to near-infrared wavelength range, with potential applications including thermophotovoltaics, thermoplasmonics, hot-electron and high temperature reflective coatings. However, the optical properties and thermal stability of TiN films strongly depend on the growth conditions, such as temperature, partial pressure of the reactive ion gas, ion energy, and substrate orientation. In this work, epitaxial TiN films are grown at 835 °C on an Al2O3 substrate using a radio frequency sputtering method. The oxidization behavior of TiN is investigated at 1000 °C under a medium vacuum condition of 2 × 10–3 mbar, which is relevant for practical technical applications, and the thermal stability at 1400 °C under a high vacuum condition of 2 × 10–6 mbar. The TiN film structure shows an unprecedented structural stability at 1000 °C for a minimum duration of 2 h under a medium vacuum condition, and an exceptional thermal stability at 1400 °C, for 8 h under a high vacuum condition, without any protective coating layer. The work reveals, for the first time to the authors’ knowledge, that the TiN film structure with columnar grains exhibits remarkable thermal stability at 1400 °C due to low-index interfaces and twin boundaries. These findings unlock the fundamental understanding of the TiN material at extreme temperatures and demonstrate a key step towards fabricating thermally stable photonic/plasmonic devices for harsh environments.
AB - Titanium nitride (TiN) has emerged as one of the most promising refractory materials for plasmonic and photonic applications at high temperatures due to its prominent optical properties along with mechanical and thermal stability. From a high temperature standpoint, TiN is a substitution for Au and Ag in the visible to near-infrared wavelength range, with potential applications including thermophotovoltaics, thermoplasmonics, hot-electron and high temperature reflective coatings. However, the optical properties and thermal stability of TiN films strongly depend on the growth conditions, such as temperature, partial pressure of the reactive ion gas, ion energy, and substrate orientation. In this work, epitaxial TiN films are grown at 835 °C on an Al2O3 substrate using a radio frequency sputtering method. The oxidization behavior of TiN is investigated at 1000 °C under a medium vacuum condition of 2 × 10–3 mbar, which is relevant for practical technical applications, and the thermal stability at 1400 °C under a high vacuum condition of 2 × 10–6 mbar. The TiN film structure shows an unprecedented structural stability at 1000 °C for a minimum duration of 2 h under a medium vacuum condition, and an exceptional thermal stability at 1400 °C, for 8 h under a high vacuum condition, without any protective coating layer. The work reveals, for the first time to the authors’ knowledge, that the TiN film structure with columnar grains exhibits remarkable thermal stability at 1400 °C due to low-index interfaces and twin boundaries. These findings unlock the fundamental understanding of the TiN material at extreme temperatures and demonstrate a key step towards fabricating thermally stable photonic/plasmonic devices for harsh environments.
KW - high-temperature stability
KW - photonics
KW - plasmonics
KW - thin films
KW - titanium nitride
UR - http://www.scopus.com/inward/record.url?scp=85106739401&partnerID=8YFLogxK
U2 - 10.1002/adom.202100323
DO - 10.1002/adom.202100323
M3 - Journal article
AN - SCOPUS:85106739401
SN - 2195-1071
VL - 9
JO - Advanced Optical Materials
JF - Advanced Optical Materials
IS - 16
M1 - 2100323
ER -