Broadband GaAsSb Nanowire Array Photodetectors for Filter-Free Multispectral Imaging

Abstract

Highly compact, filter-free multispectral photodetectors have important applications in biological imaging, face recognition, and remote sensing. In this work, we demonstrate room-temperature wavelength-selective multipixel photodetectors based on GaAs 0.94 Sb 0.06 nanowire arrays grown by metalorganic vapor phase epitaxy, providing more than 10 light detection channels covering both visible and near-infrared ranges without using any optical filters. The nanowire array geometry-related tunable spectral photoresponse has been demonstrated both theoretically and experimentally and shown to be originated from the strong and tunable resonance modes that are supported in the GaAsSb array nanowires. High responsivity and detectivity (up to 44.9 A/W and 1.2 × 10 12 cm √Hz/W at 1 V, respectively) were obtained from the array photodetectors, enabling highresolution RGB color imaging by applying such a nanowire array based single pixel imager. The results indicate that our filter-free wavelength-selective GaAsSb nanowire array photodetectors are promising candidates for the development of future high-quality multispectral imagers.

Enhanced Absorption of a Patterned Thin Germanium Layer as a High-Contrast Grating

“…In addition, it can be observed from both simulated and measured absorption spectrum that the absorption is red-shifted as the w increases with a fixed period, that means the absorber is a strong width-dependent absorption. This is due to the strong resonant modes supported in the different width of the strip would efficiently couple the incident light at different wavelengths [36]. The wavelength selectivity of this absorber is beneficial to our design of different target wavelengths, which is crucial for practical applications.…”

Flexible Microspectrometers Based on Printed Perovskite Pixels with Graded Bandgaps

“…Miniaturized spectrometers with advantages of portability and low cost and power consumption have attracted much attention due to their potential in advanced application scenarios, including wearable devices, hyperspectral imaging, and internet of things. − Computational spectrum reconstruction based on a series of response-modulated photodetectors with a gradient bandgap is one of the most promising methods for achieving such miniaturized spectroscopy systems. − For instance, Yang et al successfully demonstrate a miniaturized spectrometer at the scale of tens of micrometers using a single compositionally graded CdS x Se 1– x nanowire . Recently, halide perovskites have also been used in photodetectors for human visual-like spectrum projection, full-color detection, and multispectral recognition owing to their outstanding properties such as facile solution-process fabrication, excellent light harvesting coefficients, and tunable bandgaps. − Xu et al demonstrated a miniaturized multispectral detector based on a composition-gradient perovskite microwire detector array, offering a response edge ranging from 450 to 790 nm .…”

Perovskite photodetector-based single pixel color camera for artificial vision

“…This article provides a new perspective for exploration of new materials and strategies for the development of next generation high performance imaging camera technology. By adopting this approach, with complementary material systems and novel structures, such as III-V semiconductors 10 , 2-D materials 11 , and metasurfaces 12 , we are a step closer to mimicking of the sophisticated biological eyes that are not only sensitive to the visible light, but also to the infrared, and THz wavelengths, with associated polarization and phase information.…”