Harnessing the Interplay between Photonic Resonances and Carrier Extraction for Narrowband Germanium Nanowire Photodetectors Spanning the Visible to Infrared

Abstract

At visible wavelengths, photodetection in three channels (red, green and blue) enables color imaging. Yet the spectra of most materials provide richer information than just color, and therefore considerable interest exists for imaging with multiple spectral bands across the visible to infrared. This endeavor requires narrowband photodetection, which is generally achieved by combining broadband photodetectors with filters or spectrometers, but with added bulk and cost. Here we report, for the first time to our knowledge, vertical germanium nanowires as narrowband photodetectors. Our devices exhibit spectral response peaks that are as narrow as 40 nm and can be shifted from visible (~600 nm) to infrared (~1600 nm) wavelengths by appropriate design. The spectral selectivity arises from the nanowires acting as waveguides and, surprisingly, is enhanced by radial narrowing of the carrier collection region due to surface recombination. The incorporation of germanium into integrated circuits in a high yield and costeffective manner is well-established, making our approach promising for many detection applications.

Mid- to long-wave infrared computational spectroscopy using a subwavelength coaxial aperture array

“…Computational spectroscopy is also applicable to systems containing photodetectors with tailored responsivity spectra such as nanowires (e.g. 26,27 ). We use the recursive least squares (RLS) method.…”

Highly Efficient Near-Infrared Detector Based on Optically Resonant Dielectric Nanodisks

“…As shown in Figure 1 , the parameter a is the lattice constant of the structure. Similar structures were recently fabricated, including an array of vertical Ge-Si heterojunction nanowires demonstrating narrowband photodetection [ 15 , 16 ] and nanopillar LEDs in the form of PIN junction [ 17 ].…”

“…Our metasurface also permits tuning the excited optical modes and their spectral overlap to achieve tunable resonances in the responsivity of the device and allows for spectrally selective light detection. Therefore, it could be applied for narrowband photodetection [ 16 ] and filter-free narrowband light detection [ 44 ] which are crucial for NIR imaging and machine vision [ 45 ]. In this study, we have shown the possibility of a bandwidth of 44–65 GHz and responsivity between 0.19 and 0.43 A/W.…”

Exploiting supramolecular assemblies for filterless ultra-narrowband organic photodetectors with inkjet fabrication capability

“…[10][11][12] Nanowires were shown to provide narrowband photodetectors over a large spectral domain (600 nm -1600 nm). 21 Albeit compelling with respect to narrowband sensitivity, CCN has the drawback to increase response time and operating voltage and to decrease the external quantum efficiency (EQE) of the detector. For instance, Fang et al 11 have shown ultra-narrowband single crystal perovskite films with FWHM < 20 nm.…”