Tunable Photodetectors via in situ Thermal Conversion of TiS$_3$ to TiO$_2$

Foad Ghasemi; Riccardo Frisenda; Eduardo Flores; Nikos Papadopoulos; Robert Biele; David Perez de Lara; Herre S. J. van der Zant; Kenji Watanabe; Takashi Taniguchi; Roberto D'Agosta; Jose R. Ares; Carlos Sánchez; Isabel J. Ferrer; Andres Castellanos-Gomez

doi:10.3390/nano10040711

paper

Tunable Photodetectors via in situ Thermal Conversion of TiS $_{3}$ to TiO $_{2}$

arXiv:2006.06842 · doi:10.3390/nano10040711

Abstract

In two-dimensional materials research, oxidation is usually considered as a common source for the degradation of electronic and optoelectronic devices or even device failure. However, in some cases a controlled oxidation can open the possibility to widely tune the band structure of 2D materials. In particular, we demonstrate the controlled oxidation of titanium trisulfide (TiS $_{3}$ ), a layered semiconductor that has attracted much attention recently thanks to its quasi-1D electronic and optoelectronic properties and its direct bandgap of 1.1 eV. Heating TiS $_{3}$ in air above 300 °C gradually converts it into TiO $_{2}$ , a semiconductor with a wide bandgap of 3.2 eV with ap-plications in photo-electrochemistry and catalysis. In this work, we investigate the controlled thermal oxidation of individual TiS $_{3}$ nanoribbons and its influence on the optoelectronic properties of TiS $_{3}$ -based photodetectors. We observe a step-wise change in the cut-off wavelength from its pristine value ~1000 nm to 450 nm after subjecting the TiS $_{3}$ devices to subsequent thermal treatment cycles. Ab-initio and many-body calculations confirm an increase in the bandgap of titanium oxysulfide (TiO $_{2 - x}$ S $_{x}$ ) when increasing the amount of oxygen and reducing the amount of sulfur.

7 figures in main text, 9 figures in supp. info

Tunable Photodetectors via in situ Thermal Conversion of TiS3​ to TiO2​

Abstract

References in corpus (11)

Tunable Photodetectors via in situ Thermal Conversion of TiS $_{3}$ to TiO $_{2}$