Responsivity of quantum well infrared photodetectors at terahertz detection wavelengths

Abstract

A first-principles model of the photocurrent in quantum well infrared photodetectors ͑QWIPs͒ is derived. The model examines the responsivity, carrier capture probability and quantum efficiency. It is found that the QWIP sensitivity reaches a plateau below the 10 m detection wavelength and remains nearly constant from 10 to 50 m.

Performance Analysis of Quantum Well Infrared Photodetectors

“…The obtained value of potential φ(χ) is a general form which is different from that published in [4] = 2pel d /e and ζ = Σ η (7b) ζ represents the average normalized electron sheet density.…”

“…The density of the electron tunneling current j injected through the emitter barrier to the QW structure is presented as: (4) j m is the maximum current density from the emitter. This current density depends mainly on the doping level of the emitter; E e = dj/dx| I=0 is the absolute value of the electric field at the emitter barrier, and χ = 0 corresponds to the plane between the emitter contact layer and the extreme barrier.…”

T-Ray Sensing and Imaging

“…17,18 In an analogous manner to nonlinear optical mixing and photomixing in biased semiconductors, CW THz radiation can be coherently detected using homodyne mixing in nonlinear crystals 107 and photoconductive switches. 78,90 For CW detection with THz local oscillators, electronic detectors have been developed based on cooled photodetectors, 108 electron plasmas in semiconductors, 109,110 semiconductor superlattices, 111 mesoscopic quantum devices, 112 resonant quantum well infrared photodetectors (QWIPS) 113 and high-electron-mobility transistors (HEMTs). 114 Purely electronic systems incorporate symmetrical sources and detectors.…”

Optimal Dark Current Reduction in Quantum Well 9 µm GaAs/AlGaAs Infrared Photodetectors with Improved Detectivity

“…where is the quantum efficiency of a single well, N is the period number and P c is the quantum well capture probability [10] . The responsivity can be expressed as a function of well width:…”

“…5, increasing the number of periods decreases the dark current because of decreasing the average electric field through the device. Also, increasing the number of periods reduces the detector responsivity [10] ; hence it should be optimally designed through judicious choice. Fig.…”