Insights on hexagonal TbMnO3 for optoelectronic applications: From powders to thin films

• Published in: Journal of alloys and compounds 2021-11, Vol.883, p.160922, Article 160922
• Main Authors: Fix, T., Schmerber, G., Rehspringer, J.-L., Rastei, M.V., Roques, S., Bartringer, J., Slaoui, A.
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Circuits; Engineering Sciences; Ferroelectricity; Gadolinium; Optical properties; Optoelectronics; Oxide materials; Photoconductivity and photovoltaics; Photovoltaic cells; Pulsed laser deposition; Pulsed lasers; Room temperature; Short circuit currents; Signal and Image processing; Solar cells; Thin films; Yttrium
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.160922

•The topic of the work is hexagonal TbMnO3 (TMO).•MxTb1−xMnO3 powders with M=In, Lu, Gd, Sm, Nd, Y are fabricated.•All these powders lead to an orthorhombic MxTb1−xMnO3 phase.•Conversely, TMO, In-TMO, Y-TMO and YMnO3 films can be obtained in the hexagonal phase.•The optical, ferroelectric and photovoltaic properties of the films are assessed. The optoelectronic properties of h-TbMnO3 thin films are investigated and dopants such as Y are beneficial for the photovoltaic properties. [Display omitted] In this work, we first report on the fabrication of TbMnO3 (TMO) powders and doping with In, Lu, Gd, Sm, Nd, Y. In and Nd atoms were found to significantly reduce the cell size while preserving an orthorhombic structure. Conversely, we show that hexagonal h-TMO, indium doped TMO (h-In-TMO), yttrium doped TMO (h-Y-TMO), and YMnO3 (h-YMO) can be obtained epitaxially using pulsed laser deposition (PLD) on Pt (111)//Al2O3 (0001). The evolution of the optical properties was measured for the PLD films and a direct bandgap of 1.5–1.6 eV was found for h-TMO and doped h-TMO films. The h-TMO, h-In-TMO and h-Y-TMO showed no sign of ferroelectricity at room temperature as opposed to h-YMO. No short-circuit current in solar cell configuration was found under 1 sun illumination. However a photovoltaic behavior was observed by surface photovoltage for the h-Y-TMO and h-YMO, indicating that Y incorporation in h-TMO is helpful for the photovoltaic properties.