Infrared photodetector sensitized by InAs quantum dots embedded near an Al0.3Ga0.7As/GaAs heterointerface

Abstract

Mid-infrared sensors detect infrared radiation emitted from objects, and are actually widely used for monitoring gases and moisture as well as for imaging objects at or above room temperature. Infrared photodetectors offer fast detection, but many devices cannot provide high responsivity at room temperature. Here we demonstrate infrared sensing with high responsivity at room temperature. The central part of our device is an Al 0.3 Ga 0.7 As/GaAs heterostructure containing inAs quantum-dot (QD) layer with a 10-nm-thick GaAs spacer. In this device, the electrons that have been accumulated at the heterointerface are transferred to the conduction band of the Al 0.3 Ga 0.7 As barrier by absorbing infrared photons and the following drift due to the electric field at the interface. These intraband transitions at the heterointerface are sensitized by the QDs, suggesting that the presence of the QDs increases the strength of the intraband transition near the heterointerface. The room-temperature responsivity spectrum exhibits several peaks in the mid-infrared wavelength region, corresponding to transitions from the inAs QD and wetting layer states as well as the transition from the quantized state of the triangular potential well at the two-dimensional heterointerface. We find that the responsivity is almost independent of the temperature and the maximum value at 295 K is 0.8 A/W at ~ 6.6 µm for a bias of 1 V, where the specific detectivity is 1.8 × 10 10 cmHz 1/2 /W.

Coupled Multiphysics Modelling of Sensors for Chemical, Biomedical, and Environmental Applications with Focus on Smart Materials and Low-Dimensional Nanostructures

“…Next, we would note that zero-dimensional nanostructures have also been playing an important role in developing innovative sensing technologies. One of the examples in this direction includes longwave-infrared remote sensing and spectral imaging devices, in particular the development of quantum-dot infrared photodetectors [ 58 , 59 ]. As in the number of cases already considered by us, it should be emphasized that the knowledge of bandstructure here is critical too, because, e.g., the bias-dependent spectral response of these devices is brought about by the asymmetric bandstructure of the dot-in-a-well configuration.…”

Submonolayer stacking growth of In(Ga)As nanostructures for optoelectronic applications: an alternative for Stranski–Krastanov growth

“…We have also shown that UC occurs in QWIs most likely by biexciton Auger interaction, and that its efficiency may exceed that of QDs by proper control. This opens novel possibilities for applications such as intermediate band solar cells [52][53][54] or infrared (IR) detectors 55) based on UC.…”

On-chip light detection using integrated microdisk laser and photodetector bonded onto Si board

“…The use of In(Ga)As/GaAs QDs in microlasers as an active region provides such advantages as high operating temperature, improved temperature stability of characteristics, low threshold current, low sensitivity to nonradiative recombination [9,10]. The use of In(Ga)As/GaAs QDs in detectors helps to reduce the dark current and improve the sensitivity [11][12][13]. An 11 µm × 90 µm waveguide photodetector with InAs QDs heterogeneously integrated on Si exhibits the maximum responsivity of 0.34 A W −1 at 1310 nm and the openeye diagrams up to 12.5 Gb s −1 together with the minimum dark current of 1 µA cm −2 [14].…”