Reconfigurable and Broadband Polarimetric Photodetector

Abstract

The sensitive detection of light polarization besides the intensity and wavelength, can provide a new degree of freedom for more and clearer information of imaging targets in night, fog, and smoke environment. However, the conventional filter-integrated polarimetric photodetectors suffer from the complicated fabrication process and limited spectral range. Herein, broadband and polarization-sensitive photodetectors are achieved with reconfigurable operation mode, utilizing the linear dichroism and narrow band gap of 2D As 0.4 P 0.6 with in-plane anisotropic structure. In As 0.4 P 0.6 -MoTe 2 heterojunction device, both photo-gating and photovoltaic modes are operated and switchable, contributing to high responsivity (1590 A W −1 at 405 nm and 14.7 A W −1 at 1550 nm) and ultrafast speed (25 µs) in the wide spectral band (405-1550 nm). Interestingly, an optical reversal is observed on both linear dichroism and polarimetric photocurrent due to the wavelengthdependent polarization reverse nature of the As 0.4 P 0.6 flakes. The dichroism ratio of photocurrent can be modulated from unity to ≈10 by varying the gate voltage, enabling the reconfigurable detection mode from polarizationindependence to polarization-susceptibility. This study demonstrates a new prototype device comprising low symmetric van der Waals heterostructure, possessing the gate-tunability on both photo-gain and dichroism ratio, toward high performance, reconfigurable, broadband, and polarizationresolved photodetection and imaging applications.

Type-II Bi2O2Se/MoTe2 van der Waals Heterostructure Photodetectors with High Gate-Modulation Photovoltaic Performance

“…As the key figures of merit of photodetectors, the response speed (τ rise : photocurrent increases from 10 to 90% of its final value)/decay time (τ decay : photocurrent falls from 90 to 10% of its beginning value), noise, and specific detectivity are also characterized. As displayed in Figure e, τ rise /τ decay values of 157/141 μs ( V g = −60 V) and 208/173 μs ( V g = 0 V) were obtained at a frequency of 100 Hz in Figure S8a–d. , The Fourier transform of the dark current traces gives the noise spectral density ( S n ) as a function of frequency, as shown in Figure S9b ( V g = 0 V) and Figure S9d ( V g = −60 V). ,, At low frequencies, a 1/ f noise component is observed, attributed to interface traps or defects, , whereas at high frequencies above 10 Hz, the device reaches a noise floor with very low white noise, about 2 × 10 –15 A Hz –1/2 , which is independent of the frequency and close to the scattered particle noise floor. Moreover, at V g = −60 V, a lower S n was obtained, probably due to MoTe 2 in the heterojunction being electrostatically tuned to P-type doping, creating a larger built-in electric field.…”

“…As displayed in Figure 5e, τ rise /τ decay values of 157/141 μs (V g = −60 V) and 208/173 μs (V g = 0 V) were obtained at a frequency of 100 Hz in Figure S8a−d. 35,36 The Fourier transform of the dark current traces gives the noise spectral density (S n ) as a function of frequency, as shown in Figure S9b (V g = 0 V) and Figure S9d (V g = −60 V). 4,37,38 At low frequencies, a 1/f noise component is observed, attributed to interface traps or defects, 4,37 whereas at high frequencies above 10 Hz, the device reaches a noise floor with very low white noise, about 2 × 10 −15 A Hz −1/2 , which is independent of the frequency and close to the scattered particle noise floor.…”

Vertical 1T’‐WTe2/WS2 Schottky‐Barrier Phototransistor with Polarity‐Switching Behavior

“…[10] Above all, the reconfigurable polarization photodetection of our fabricated WTe 2 /WS 2 phototransistor under V g control can apply several modes such as polarimetric sensor or not dependent on the specific application circumstances. [67] Moreover, the imaging capability of a self-driven photodetector to collect optical signals and acquire high-resolution image information is of great importance in remote sensing detection. A light-emitting diode (LED) of 620 nm with a spot diameter of 27 μm at light power of 800 μW is implemented by a commercial single-pixel modulus (see in Measurement part).…”

“…[ 10 ] Above all, the reconfigurable polarization photodetection of our fabricated WTe 2 /WS 2 phototransistor under V g control can apply several modes such as polarimetric sensor or not dependent on the specific application circumstances. [ 67 ]…”

Low-dimensional van der Waals materials for linear-polarization-sensitive photodetection: materials, polarizing strategies and applications

“…In addition, a superior linear DR of ≈18 has been realized upon 635 nm illumination. Most recently, Li et al have demonstrated self-powered polarizationresolved photodetection from visible to near infrared based on a b-As 0.4 P 0.6 /MoTe 2 heterojunction [124].…”