High responsivity quantum cascade detectors with bound-to-miniband diagonal transition

Abstract

We demonstrate a long-wavelength infrared quantum cascade detector (QCD) that operates at a wavelength of 10 μm, in which the active diagonal transition for the electrons occurs from a fundamental energy level into a miniband in adjacent coupled quantum wells. When compared with a bound-to-bound diagonal transition-based QCD, the use of a miniband as the final transition state increases the absorption strength and enhances the electron extraction efficiency of the device, leading to QCD responsivities of 75 at 180 and 30 mA/W at 300 K for 10.55 μm wavelength operation.

Recent Progress in Improving the Performance of Infrared Photodetectors via Optical Field Manipulations

“…Although some solutions were proposed to enhance devices' performance, the quantum efficiency is still below 40% [68]. Besides, there are some works on increasing the operating temperature to room temperature [69,70], but the detectivity is still below 10 9 Jones. T2SL infrared photodetectors could alternate HgCdTe infrared photodetectors in the waveband range of LWIR [71][72][73].…”

Electrical flicker-noise analysis based on trapping and de-trapping model in quantum-cascade detectors

“…[1,2,6] Various design concepts of the active region have been proposed with the aim of improving the responsivity and operation temperature, and bandwidth of the response spectrum. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Owing to progress in the design of the active region, as well as their low-noise property with bias-free photovoltaic operation, the noise-equivalent power of QC detectors compares favorably with the other uncooled IR detectors, such as mercury-cadmium-telluride detectors. [22,23] In addition, highspeed operation with a response time on the order of picoseconds has been demonstrated in mid-IR QC detectors for the detection of a high-frequency heterodyne beat signal, [24,25] microwave rectification, [26] and the observation of an impulse response of a femto-second optical pulse.…”

Quantum cascade detectors with enhanced responsivity using coupled double-well structures

“…17) They increased the responsivity by a factor of five. Recently, we have demonstrated a bound-to-miniband diagonal transition QCD with an extraction efficiency close to 1, which exhibited a high responsivity of 75 mA W −1 at 180 K. 18) So far, the responsivity of a QCD is still below 100 mA W −1 without external optical antennas 17) or optical waveguides 19) although the extraction and absorption efficiency in the active region has been effectively increased. [16][17][18]20) In this work, we demonstrate a high photo-response QCD with a coupled double-absorption-well structure.…”

“…QWs W 4 and W 5 are also coupled to extend the length of the extractor, thereby reducing the bypass caused by carrier diffusion between adjacent doped QWs. 18) The two-dimensional absorption coefficient α 2D for the transitions from E 10 /E 20 to final states using Fermi's golden rule is given by: 1)…”