Photovoltaic quantum dot quantum cascade infrared photodetector

Abstract

Design and characterization of a quantum dot quantum cascade detector for photovoltaic midwave infrared photodetection (λpeak = 5.5 μm) is demonstrated. The quantum cascade barrier region provides the internal electric field to transfer photoexcited electrons into quantum dots of the next stack, enabling zero bias operation. Increased carrier relaxation time for intersubband transitions in quantum dots provides a distinct advantage for the carrier transport. Responsivity of 10 mA/W and detectivity of 9 × 109 cm Hz1/2 W−1 at 77 K for f/2 optics has been obtained at zero bias. Dark current density is 6.5 × 10−7A cm−2, at 80 K at zero bias.

Quantum Dot Quantum Cascade Detector on Si Substrate

“…The devices show dark current density of 2.1×10 -8 A/cm 2 , the calculated resistancearea product (R0A) is 1.13×10 7 Ω.cm 2 . These performance are comparable to the other QCD grown on native III-V substrate [3]. The normal incident optical response of the Si QCD was measured by Fourier transform infrared spectrometer, and calibrated by a blackbody resource at 700℃ under zero bias as shown in Fig 3(a).…”

Broadband Ge/SiGe quantum dot photodetector on pseudosubstrate

“…In Figure 2, we can see that the current from the background radiation is equal to the dark current at 100 K and negative bias. This temperature is higher than that measured for Ge/Si QDIP [13] and GeSi/Si QWIP [17] operating in long-wave IR region and exceeds T BLIP found for many n-type InAs QD-based detectors [18-21]. …”

Physics of Internal Photoemission and Its Infrared Applications in the Low-Energy Limit

“…Photovoltaic detectors are attractive for achieving (i) extremely low noise, (ii) high impedance, and (iii) low power dissipation, compared to photoconductive detectors [45]. Various device concepts based on -junctions [46], quantum well (QW) [47], quantum dot (QD) [48,49], type-II InAs/GaSb [50], and quantum cascade (QCD) structures [49,51] have been explored to implement photovoltaic operation. One of the key factors is to have a built-in potential to sweep out the photocarriers without using an external electric field.…”