Light-hole and heavy-hole transitions for high-temperature long-wavelength infrared detection

Abstract

Hole transitions from the heavy-hole ͑hh͒ to the light-hole ͑lh͒ band contributing to the 4-10 m response range are reported on p-GaAs/ AlGaAs detectors. The detectors show a spectral response up to 16.5 m, operating up to a temperature of 330 K where the lh-hh response is superimposed on the free-carrier response. Two characteristic peaks observed between 5-7 m are in good agreement with corresponding energy separations of the lh and hh bands and thus originated from lh-hh transitions. Results will be useful for designing multi-spectral detection which could be realized on a single p-GaAs structure.

Near‐Room‐Temperature Mid‐Infrared Quantum Well Photodetector

“…Figure 3 illustrates its measured detectivity. The detectivity for the device saturates near 2.8 × 10 10 Jones at temperature below ∼ 145 K. The maximum detectivity is observed near 2.2 × 10 9 Jones for > 180 K (TEC achievable operation). The detector shows an abrupt change in behavior between 140K and 160K, roughly corresponding to a transition from background-limited performance to a thermal-noise-limited performance regime.…”

“…Those devices would require > 10 4 W/cm 2 (10 mW for a 10 µ m × 10 µ m area device) laser power to operate at room temperature with photon noise limited performance. [9][10] High thermal conductivity indiumphosphide based quantum cascade QWIPs have demonstrated improved performance, but at low background infrared limited performance temperature and, to date, with ill-controlled activation energies. [ 8 , 11 ] Here, we employ an InGaAs/AlGaAs/GaAs materials approach for 5 µ m absorption wavelength photovoltaic design in quantum cascade detector (QCD) low-noise format.…”

Wavelength-extended photovoltaic infrared photodetectors

“…The D * value of SP1007 is 10 5 times higher than 30-period photoconductive detectors previously reported. 8 FIG . 4. (a) Photovoltaic response measured by using different long-pass filters (k CO is the cut-on wavelength).…”

“…According to R 0 A $ expðÀE A =kTÞ, the R 0 A value (at 80 K) of our detector with E A ¼ 0.40 eV (responding up to 8 lm) is nearly 10 15 times higher than a conventional detector with E A of 0.155 eV (without wavelength extension, also responding up to 8 lm), which gives nearly 10 7 improvement in D * . To experimentally evaluate the D * improvement factor, same type of internal-photoemission detectors 8 was used, as shown in Fig. 3(b) (this detector contains 30 periods of emitters and barriers), which is nearly 10 5 times less than the present detector.…”

“…Experimentally, D * of the 8-lmthreshold single-emitter detector reported here is 10 5 times higher than that of a previously reported 30-period detector. 8 The detector architecture uses the standard structure of internal-photoemission detectors, 8 in which a highly p-type doped GaAs acts as the photon absorber and emitter. Figure 1(a) shows the valence band, which has a non-symmetrical band configuration.…”