A quantum well-integrated metallic microcavity infrared photodetector is designed and fabricated to achieve highly polarized narrowband wavelength selective detection. Linear grooves are etched on top of the mesa and then the whole device is completely coated with Ti/Au to form an open metallic microcavity, and the resonant mode of the metallic cavity can be detected by the embedded quantum well active layer. The obtained devices show very narrow wavelength selective detection ability as well as strong polarization-dependent characteristics. High performances such as a quality factor of 60 and a polarization extinction ratio of 146 are noticed. Our work provides a promising basis for developing highly integrated infrared cameras with a remarkable performance.

The complex GaAs/AlGaAs core–multishell nanowire heterostructure was epitaxially grown, which has a long photoluminescence lifetime.

A novel high-efficiency microcavity structure of quantum wells sandwiched between periodic heavily Si-doped GaAs top contact gratings and bottom contact film has been proposed as the optical coupler of a terahertz quantum well photodetector (THz QWP). Similar to metal at visible light, highly doped semiconductors exhibit plasma frequencies at mid- and far-infrared wavelengths. The intersubband absorption spectra and electric field distribution of the microcavity THz QWP are calculated with the finite difference time-domain method. Our results indicate that the frequency of the surface plasmon polariton can be tuned to the microcavity resonant mode under an optimized structure and the intersubband absorption is efficiently enhanced by the microcavity structure. When the doping concentration of the contact exceeds 10¹⁸cm⁻³, the intersubband absorption of the microcavity THz QWP at the response wavelength is over one order of magnitude higher than that of the standard 45° device. In addition, the angle of the incident light only influences the intensity of the absorptivity, indicating that the designed device was independent of the periodic surface structure.

Bi₂Te_3 − xSe_x photoconductive detectors are attractive due to their linear photo-response (LPR), potential in ultrabroadband photo-detection, and compatibility with CMOS technology. However, as a fundamental issue for photo-detectors, the weak-light photo-response of Bi₂Te_3 − xSe_x detectors was covered by the bolometric response, the photo-thermoelectric effect, and the 300 K background black-body radiation from the optical window. Here, using a window-less system, we systematically measure the weak-light photo-response of a Bi₂Te₃ photoconductive detector. The bolometric response and photo-thermoelectric effect are carefully excluded. It shows that LPR can persist to a small light power density of P < 10⁻⁸W/cm². Meanwhile, the response is maximized at ∼80 K temperature. We suggest that the LPR is rooted in the unique carrier recombination configuration of Bi₂Te₃, which can result in a constant lifetime for light-generated carriers. The concerned trap level is manifested by a negative photo-response under reduced light intensity. The signature of surface state related signal is presented as a photo-response with the maximum at ∼10 K temperature, which is fragile under increased light intensity. Although the window-less photo-response measurement is at its early stage, it provides a perspective which is different from that of the traditional optical-window based measurement.

Metalenses play an important role in optoelectronic integrated devices, given their advantages in miniaturization and integration. Due to its high aspect ratio subwavelength structure, fabricating metalenses requires a high-level dry etching technology. Consequently, structure deformation of the metalens will exist if the etching process of the material is not mature enough, which will impair the metalens’ performance. In this paper, a polarization-independent InP dielectric metalens is designed to focus the incident light from air into the substrate, which is used for monolithically integrating with the InGaAs/InP photodetector in the future. Subsequently, with the simulation method, we investigated the impact of the structure deformation on the metalens’ performance, which was found in our InP dry etching process development. We have found that the sidewall slope and aspect ratio-dependent etching effect greatly impaired the focusing efficiency because of the phase modulation deviation. To solve this problem, we proposed a manufacturing-tolerant design method, which effectively improved the performance of the device with structural deformation. Our work is instructive for developing metalenses and can accelerate their integration application.