Sub-monolayer quantum dot quantum cascade mid-infrared photodetector

Abstract

In this work, we demonstrate a sub-monolayer quantum dot quantum cascade photodetector (SML QD-QCD) grown on GaAs for photovoltaic mid-infrared photo-detection. The detector shows normal-incident peak responsivity of 1.90 mA/W at the wavelength of 6.05 μm and a resistance-area product of 1.54×10 8 Ω﹒cm 2 at 77 K. The corresponding specific detectivity is 3.22×10 11 cm•Hz 1/2 /W. Quantum cascade photodetector (QCD) has recently attracted substantial interests due to the advantage that no external bias voltage is required for operation, which leads to zero dark current, much lower noise, relatively high operating temperature, and low power dissipation 1. Quantum cascade photodetectors based on quantum well (QW-QCDs) have been demonstrated in short infrared wavelength 2 , mid infrared wavelength 3 4 and long infrared wavelength ranges 5. However, for QW-QCDs, there is no intrinsic response to normal incidence light, due to the inter-subband transition selection rules of quantum wells. Plasmonic waveguides 6 , grating 7 , and photonic crystal slab 8 have been used to make the QW-QCD sensitive to normal incident light. Quantum dot infrared photodetectors (QDIP) have been extensively studied due to the advantages of three dimensional confinement of carriers, which is expect to have lower dark current, long excited state lifetime and intrinsic sensitivity to normal incident light 9. In order to achieve normal incidence intra-band response in QCD, the quantum well layer used for light absorption is replaced by quantum dots, which is very similar to the case of quantum well infrared photodetector versus quantum dot infrared photodetector. Moreover, due to the fact that the carrier capture time in quantum dots is much _____________________________ a) Jian Huang and Daqian Guo contributed equally to this work.

Mid-Wave Infrared InAs/GaSb Type-II Superlattice Photodetector With n-B-p Design Grown on GaAs Substrate

“…[12]. The dislocations density d is estimated to be ~510 7 cm -2 , based on the equation d = (FWHM/2b) 2 , where the Burgers vector b is 0.431 nm [17].…”

“…Additional works are required to increase the QE of our device by optimizing the crystal quality of absorber. Finally, the Johnson noise-limited specific detectivity D* of the T2SL device is calculated by [18,21,22]: (2) where Rp is the peak responsivity, A is the device mesa area, kB is Boltzmann's constant, T is the temperature of the device, R0 is the differential resistance under zero bias, and q is the electron charge. Specific detectivity curves calculated at different temperatures are shown in Fig.…”

“…In the IMF growth mode, both 90° and 60° misfit dislocations (MDs) could present at the GaSb/GaAs interface. The 90° MDs are pure edge type dislocations which propagate laterally along the [110] and [1][2][3][4][5][6][7][8][9][10] directions; the 60° MDs can generate vertical propagated threading dislocations (TDs) along the (111) planes into the device region, which could contribute to high level of dark current [13,14]. By using the IMF growth mode, T2SL detectors demonstrated on the highly lattice mismatched substrates have shown promising results comparing with the counterparts grown on the native substrates [10,13].…”

Exploring Electronic and Excitonic Processes toward Efficient Deep-Red CuInS2/ZnS Quantum-Dot Light-Emitting Diodes

“…Colloidal semiconductor quantum dots (QDs) have been emerging as a class of attractive materials for optoelectronic applications in the past three decades, such as solar cells, 1,2 detectors, 3,4 and light emitting diodes. 5−11 Their unique optical properties are generating much excitement for the QD lightemitting diodes (QLEDs) in lighting and display applications.…”

“…Colloidal semiconductor quantum dots (QDs) have been emerging as a class of attractive materials for optoelectronic applications in the past three decades, such as solar cells, , detectors, , and light emitting diodes. − Their unique optical properties are generating much excitement for the QD light-emitting diodes (QLEDs) in lighting and display applications. , Currently, the performance of QLEDs has rapidly been improved with over 20% external quantum efficiency (EQE) and longer than 280 000 h device operation lifetime benefiting from the optimization of both QD synthesis and device design . However, most of the efficient QLEDs are still dependent on the Cd-based QDs to date.…”