Author
Xinjian Yi
Bio: Xinjian Yi is an academic researcher from Huazhong University of Science and Technology. The author has contributed to research in topics: Thin film & Microlens. The author has an hindex of 19, co-authored 90 publications receiving 1444 citations.
Papers
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TL;DR: In this article, the authors describe the design and fabrication of an eight-element uncooled microbolometer linear array using vanadium dioxide (VO 2 ) thin films and micromachining technology.
Abstract: Vanadium dioxide (VO 2 ) thin films are materials for uncooled microbolometer due to their high temperature coefficient of resistance (TCR) at room temperature. This paper describes the design and fabrication of eight-element uncooled microbolometer linear array using the films and micromachining technology. The characteristics of the array is investigated in the spectral region of 8–12 μm. The fabricated detectors exhibit responsivity of over 10 kV/W, detectivity of approximate 1.94×10 8 cm Hz 1/2 /W, and thermal time constant of 11 ms, at 300 K and at a frequency of 30 Hz. Furthermore, the uncorrected response uniformity of the linear array bolometers is less than 20%.
184 citations
Journal Article•
TL;DR: By studying the minority electron concentration as a function of temperature in the range 100-300 K, this work unambiguously confirmed the long-standing theoretical prediction that quantum confinement should convert Bi from a semimetal to a semiconductor at a critical thickness on the order of 300 A.
Abstract: Field- and temperature-dependent magnetotransport measurements on Bi layers grown by molecular-beam epitaxy have been analyzed by mixed-conduction techniques. In the thin-film limit, the net hole density scales inversely with layer thickness while the mobility scales linearly. By studying the minority electron concentration as a function of temperature in the range 100-300 K, we have unambiguously confirmed the long-standing theoretical prediction that quantum confinement should convert Bi from a semimetal to a semiconductor at a critical thickness on the order of 300 A
183 citations
TL;DR: In this paper, the authors presented a method to make vanadium dioxide (VO 2 ) crystallites on silicon substrates by reactive ion beam sputtering, and the thickness of the thin film is about 100nm.
Abstract: This paper presents a method to make vanadium dioxide (VO 2 ) crystallites on silicon substrates by reactive ion beam sputtering. The thickness of the thin film is about 100 nm. The transmittance of the semiconducting phase VO 2 is about 54% and it is reduced to as low as 3% in metal phase at the wavelength of 10.6 μm. And the ratio of the transmittance of these two states is measured being 18:1. When a destructive light intensity is above 0.85 W/cm 2 at 10.6 μm, most of the light could be reflected by the thin film, thus the sensitive infrared detector is protected from strong laser radiation.
86 citations
TL;DR: In this article, the authors describe the deposition of poly-crystal mixed vanadium oxide thin films on substrates of quartz glass and Si(1 0 0 ) by reactive ion-beam sputtering followed by post-deposition annealing, and the fabrication of experimental linear uncooled microbolometer array infrared detectors on the quartz substrate as well.
81 citations
TL;DR: In this paper, a novel optical switches based on VO2 thin film on substrates of silicon (1.0-0) has been fabricated, and the vanadium dioxide thin films were deposited by reactive ion beam sputtering followed by a post-annealing.
81 citations
Cited by
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TL;DR: Transparent conductors (TCs) have a multitude of applications for solar energy utilization and for energy savings, especially in buildings as discussed by the authors, which leads naturally to considerations of spectral selectivity, angular selectivity, and temporal variability of TCs, as covered in three subsequent sections.
1,471 citations
TL;DR: In this article, a gapless phase between the spin Hall and the insulator phases in 3D was investigated in inversion-asymmetric systems, and it was shown that the existence of such a phase stems from the topological nature of gapless points (diabolical points) in three dimensions, but not in 2D.
Abstract: Phase transitions between the quantum spin Hall (QSH) and the insulator phases in three dimensions (3D) are studied. We find that in inversion-asymmetric systems there appears a gapless phase between the QSH and insulator phases in 3D which is in contrast with the 2D case. Existence of this gapless phase stems from a topological nature of gapless points (diabolical points) in 3D, but not in 2D.
979 citations
570 citations
TL;DR: In this paper, the authors show that perfect absorption can be achieved in a system comprising a single lossy dielectric layer of thickness much smaller than the incident wavelength on an opaque substrate by utilizing the nontrivial phase shifts at interfaces between lossy media.
Abstract: We show that perfect absorption can be achieved in a system comprising a single lossy dielectric layer of thickness much smaller than the incident wavelength on an opaque substrate by utilizing the nontrivial phase shifts at interfaces between lossy media. This design is implemented with an ultra-thin (∼λ/65) vanadium dioxide (VO2) layer on sapphire, temperature tuned in the vicinity of the VO2 insulator-to-metal phase transition, leading to 99.75% absorption at λ = 11.6 μm. The structural simplicity and large tuning range (from ∼80% to 0.25% in reflectivity) are promising for thermal emitters, modulators, and bolometers.
536 citations
TL;DR: It is theoretically predicted that two-dimensional bismuth will show the quantum spin-Hall effect, both by calculating the helical edge states, and by showing the nontriviality of the Z2 topological number.
Abstract: We show that the spin-Hall conductivity in insulators is related to a magnetic susceptibility representing the strength of the spin-orbit coupling. We use this relationship as a guiding principle to search real materials showing quantum spin-Hall effect. As a result, we theoretically predict that two-dimensional bismuth will show the quantum spin-Hall effect, both by calculating the helical edge states, and by showing the nontriviality of the ${Z}_{2}$ topological number, and propose possible experiments.
525 citations