High-Performance Shortwave Infrared Detector Based on Multilayer Carbon Nanotube Films

Abstract

Carbon nanotube (CNT) is an ideal candidate material for shortwave infrared (SWIR) detectors due to its large band gap tunability, strong infrared light absorption, and high mobility. Furthermore, the photodetectors based on CNT can be prepared on any substrate using a low-temperature process, which is conducive to three-dimensional (3D) integration. However, owing to the absorption limitation (<2%) of a single-layer network CNT film with low density, the photodetectors of CNT film show low photocurrent responsivity and detectivity. In this paper, we optimize the thickness of the high-purity semiconducting network CNT films to increase the photocurrent responsivity of the photodetectors. When the thickness of network CNT film is about 5 nm, the responsivity of the zero-bias voltage can reach 32 mA/W at 1800 nm wavelength. Then, using stacked CNT films and contact electrode design, the photodetectors exhibit a maximum responsivity of 120 mA/W at 1800 nm wavelength. The photodetectors with stacked CNT films and local n-type channel doping demonstrated a wide response spectral range of 1200–2100 nm, a peak detectivity of 3.94 × 109 Jones at room temperature, and a linear dynamic range over 118 dB. Moreover, the peak detectivity is over 2.27 × 1011 Jones when the temperature is 180 K. Our work demonstrates the potential of the CNT film for future SWIR imaging at a low cost.

Shortwave Infrared Polarization Imaging and Monolithic Integrated Polarization Amplification Systems Based on Aligned Carbon Nanotube Arrays

“…The amplified anisotropic ratio is 34 under incident wavelengths of 1600 nm (Figure S6b, Supporting Information). Figure 5e exhibits the anisotropic ratio of the CNT polarization-sensitive photodetector and MIPAS compared with InGaAs, [10] CNT, [29] 2D materials, [48][49][50] and the heterojunction [51][52][53] polarization-sensitive photodetector in the SWIR band. Our MIPAS based on the A-CNT arrays exhibits maximum anisotropic ratios of 173 and 243 at 1800 and 2000 nm wavelengths, respectively.…”

“…Based on the well-aligned CNT arrays, we constructed an asymmetric palladium (Pd) -hafnium (Hf) contact (APHC) polarization-sensitive photodetector with a local n-type doping structure that had been demonstrated to improve the performance of the photodetector by reducing the dark current. [29,34] The structure of the doped APHC (D-APHC) photodetector is shown in Figure 2a with a channel width of 20 μm and channel length of ≈500 nm, where Pd and Hf are used as the p-type and n-type electrodes, respectively. The local n-type doping layer is composed of ultrathin YO x and HfO 2 insulators with thicknesses of 5 and 30 nm, respectively, covering half of the photodetector channel (≈250 nm) near the Hf electrode.…”

“…[27,28] However, the thermal detector usually has a low special detectivity compared to the photovoltaic photodetector due to a larger dark current than the CNT film photovoltaic photodetector. [29] The Pt (platinum)-Sc (scandium) asymmetric photovoltaic photodetector based on the CNT arrays have been reported to exhibit an anisotropic ratio of more than 5 at 1.55 μm. However, the photodetector showed low external quantum efficiency due to the low CNT density (≈30 CNTs per μm) and the nonoptimized device structure.…”