Search

Inclined epitaxial La 1−x Ca x MnO 3 films based on the light-induced transverse thermoelectric (LITT) effect have attracted significant attention in fast light/thermal detection. In this work, a series of inclined La 1−x Ca x MnO 3 (0.1≤x≤0.8) films are fabricated based on a home-designed MOCVD system by adjusting the ratio of La/Ca sources. The composition-induced microstructure for La 1−x Ca x MnO 3 films is revealed. La 1−x Ca x MnO 3 tends to form a single orientation under a small lattice mismatch with the substrate, while with a multi-domain structure under an obvious mismatch, significant lattice distortions are observed in the films. With increasing Ca content, the electrical conductivity gradually increases, which is responsible for enhanced response voltage from 5.5 V for Ca10 to 25.5 V for Ca40. However, with a further increase in conductivity, the response voltage gradually decreases, which may be attributed to the deteriorated anisotropic Seebeck coefficient. Benefitting from enhanced conductivity, the response time decreases from 2984 ns for Ca10 to 58 ns for Ca60, which increases to 80 ns for Ca80 due to enhanced phonon scattering originating from the lattice distortions. This work may serve as a reference for modulating the LITT effect based on electron/phonon transport for other material systems applied in fast light/thermal detection. [Display omitted] • Inclined La 1−x Ca x MnO 3 (0.1≤x≤0.8) with good biaxial texture are prepared by MOCVD. • Composition-induced microstructure is revealed for La 1−x Ca x MnO 3 films. • Increased conductivity conduces to enhance LITT voltage and reduce response time. • Enhanced phonon scattering from lattice distortions prolongs the response time. [ABSTRACT FROM AUTHOR]

The efficient preparation of inclined La 1-x Ca x MnO 3 (LCMO) films with excellent light-induced transverse thermoelectric (LITT) performance on c -axis miscut 12° SrTiO 3 single crystal substrates is achieved based on the home-designed metal-organic chemical vapor deposition (MOCVD) system. The LCMO films with the thickness of 300 nm are prepared in 1 min, and the preparation efficiency reaches 300 nm/min. Under the radiation of 248 nm pulsed laser with the duration time of 28 ns, the voltage signal of LCMO films shows high sensitivity of 3.13 V/mJ and fast response time of 28 ns, superior to the LITT performance of the reported LCMO under the irradiation of pulsed laser with similar wavelength and duration time. The improvement of LITT performance originates from good electrical conductivity and biaxial texture. Additionally, under the radiation of 900 nm continuous laser, the obvious response voltages can be detected in the LCMO films, and the voltage amplitudes increase linearly with increasing laser power densities. These results demonstrate the application potential of the light detectors composed of LCMO films based on the efficient preparation of MOCVD, and may provide a good prospect for developing low-cost and high-performance light detectors based on the LITT effect. • Efficient preparation of inclined La 1-x Ca x MnO 3 films is achieved based on MOCVD. • The inclined La 1-x Ca x MnO 3 films show outstanding LITT performance. • Good conductivity and biaxial texture are the keys to enhance LITT effect. [ABSTRACT FROM AUTHOR]

• Highly c -axis oriented YBCO films are prepared on miscut 12° LaAlO 3 substrates. • The ALTP heat flux sensor with high sensitivity of 17.54 μV/(kW/m2) is obtained. • The response frequency of ALTP heat flux sensor is over 1 MHz at −3dB. The atomic layer thermopile (ALTP) heat flux sensor based on highly c -axis oriented YBa 2 Cu 3 O 7-δ (YBCO) films prepared on miscut 12° LaAlO 3 substrates using magnetron sputtering is achieved. Benefiting from good biaxial texture, the YBCO film maintains a large Seebeck coefficient anisotropy, so the sensitivity of the ALTP heat flux sensor reaches 17.54 μV/(kW/m2). In addition, the response frequency of the sensor is higher than 1 MHz due to the high electrical conductivity of the prepared YBCO films, which is also higher than the current maximum (650 kHz) reported in the literature. These results indicate that our ALTP heat flux sensor can realize high-frequency heat flux detection above 1 MHz. [ABSTRACT FROM AUTHOR]