Responsivity

About: Responsivity is a research topic. Over the lifetime, 9918 publications have been published within this topic receiving 186118 citations.

Characterizations of VO2-based uncooled microbolometer linear array

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%.

GeSn/Ge heterostructure short-wave infrared photodetectors on silicon

Abstract: A surface-illuminated photoconductive detector based on Ge0.91Sn0.09 quantum wells with Ge barriers grown on a silicon substrate is demonstrated. Photodetection up to 2.2µm is achieved with a responsivity of 0.1 A/W for 5V bias. The spectral absorption characteristics are analyzed as a function of the GeSn/Ge heterostructure parameters. This work demonstrates that GeSn/Ge heterostructures can be used to developed SOI waveguide integrated photodetectors for short-wave infrared applications.

Active Terahertz Imaging Using Schottky Diodes in CMOS: Array and 860-GHz Pixel

Abstract: Schottky-barrier diodes (SBD's) fabricated in CMOS without process modification are shown to be suitable for active THz imaging applications Using a compact passive-pixel array architecture, a fully-integrated 280-GHz 4 × 4 imager is demonstrated At 1-MHz input modulation frequency, the measured peak responsivity is 51 kV/W with ±20% variation among the pixels The measured minimum NEP is 29 pW/Hz1/2 Additionally, an 860-GHz SBD detector is implemented by reducing the number of unit cells in the diode, and by exploiting the efficiency improvement of patch antenna with frequency The measured NEP is 42 pW/Hz1/2 at 1-MHz modulation frequency This is competitive to the best reported performance of MOSFET-based pixel measured without attaching an external silicon lens (66 pW/Hz1/2 at 1 THz and 40 pW/Hz1/2 at 650 GHz) Given that incorporating the 280-GHz detector into an array increased the NEP by ~ 20%, the 860-GHz imager array should also have the similar NEP as that for an individual detector The circuits were utilized in a setup that requires neither mirrors nor lenses to form THz images These suggest that an affordable and portable fully-integrated CMOS THz imager is possible

High-performance 4H-SiC-based ultraviolet p-i-n photodetector

Abstract: A high-performance 4H-SiC p-i-n photodetector for visible-blind ultraviolet (UV) applications has been designed and fabricated. The electrical and optical characteristics were measured at room temperature. The photodetector suffered from significant dark current of 2.5 pA/mm2 at reverse bias of 5 V, and the UV light photocurrent was larger than four orders of magnitude higher than the dark current. The built-in potential and the unintentional i-layer doping concentration were obtained from capacitance-voltage (C-V) measurements. The spectral peak responsivity of the detector reached 0.13 A/W at a wavelength of 270 nm, corresponding to a maximum external quantum efficiency of ∼61%. And the ratio of responsivity at 270 nm to that at 380 nm was >103. The characteristics imply that the photodetector has a great improved ultraviolet-visible rejection ratio which is needed for ultraviolet signal detection.

The General Theory of Bolometer Performance

Abstract: A general phenomenological theory of the static and dynamic behavior of bolometers is presented. The theory assumes as given the fundamental relations between the temperature and resistance of the bolometer, and the past history of the power dissipated within it. From these basic properties are derived a number of the properties of more immediate interest, such as electrical impedance, responsivity as a function of frequency, and the static load curve.Several equivalent circuits are developed to represent the behavior of the bolometer as a function of frequency at a single operating point. A two-terminal equivalent circuit is described that represents the electrical impedance as a function of frequency. In order to represent the response of the bolometer to incident radiation as a function of frequency, a four-terminal equivalent circuit is described.An electrical bridge is described that permits one to measure by purely electrical means the electrical response that a bolometer would have to radiation of any given time dependence, including radiation that varies sinusoidally. By purely electrical means and without the need of a radiation source (calibrated or otherwise), the bridge provides a precise measurement of the bolometer’s responsivity (output volts per watt of incident radiation) as a function of frequency. An electrical signal S(t) at the input of the bridge produces the same electrical output as would be produced in the normal use of the bolometer by a radiation signal with the same wave form as S(t).The presentation is in three parts: static performance; stability; and dynamic performance.