Investigation of multi-color, broadband quantum well infrared photodetectors with digital graded superlattice barrier and linear-graded barrier for long wavelength infrared applications

Modeling of intersubband transitions in quantum well infrared photodetectors with complex well-barrier structures

“…[3]. This InGaAs/AlGaAs QWIP consists of It's seen that excited states (E2-E8) go downward evidently while the ground state (El) remains relatively unchangeable with increasing bias since the height of LGB decreases gradually.…”

“…In addition to the conventional single-color QWIPs with narrow response bandwidth, multi-color and broadband QWIPs that employed complex quantum well (QW) structures for advanced applications have also emerged in recent years [2][3][4], such as the broadband QWIP with digital graded superlattice barrier or linear graded barrier [3] and the near-and mid-infrared QWIP using GaAs/InxGal xAs/ InyGa1_yAs multiple step QW [4]. For QWIP structures with complex potential profiles, the theoretical calculations are very complicated generally.…”

Modeling of intersubband transitions in quantum well infrared photodetectors with complex potential profiles

“…The QWIP structure chosen in the calculation is the voltage-tunable InGaAs/Al x Ga 1−x As QWIP with linear-graded barriers (LGBs) for broad-band infrared photodetection (Lee et al 2001). Figure 1 shows the schematic potential profile in the conduction band of this structure.…”

“…In addition to the conventional single-color QWIPs with narrow response bandwidths, multi-color and broadband QWIPs which employ complex well and barrier structures for advanced applications have also been reported (Lenchyshyn et al 1996;Lee et al 2001;Touse et al 2005). The theoretical analyses on quantum wells (QWs) with non-rectangular potential profiles are complicated generally and most reported work is based on the single band model that ignores the band coupling effects.…”

Design of broadband QWIPs for operation above BLIP temperature

“…Several approaches are used to get a broadband response with QWIPs. In particular, superlattices [2] and digital graded barriers [3] in the active layers take advantage of transitions between minibands in the first case, and multiple transitions in the second case. Moreover, different papers report stacked [4] and interlaced [5] (or intermixing [6]) designs using regular QWIPs.…”