Efficient Avalanche Photodiodes with a WSe₂/MoS₂ Heterostructure via Two-Photon Absorption

Abstract

Two-dimensional (2D) materials-based photodetectors in the infrared range hold the key to enabling a wide range of optoelectronics applications including infrared imaging and optical communications. While there exist 2D materials with a narrow bandgap sensitive to infrared photons, a two-photon absorption (TPA) process can also enable infrared photodetection in well-established 2D materials with large bandgaps such as WSe2 and MoS2. However, most of the TPA photodetectors suffer from low responsivity, preventing this method from being widely adopted for infrared photodetection. Herein, we experimentally demonstrate 2D materials-based TPA avalanche photodiodes achieving an ultrahigh responsivity. The WSe2/MoS2 heterostructure absorbs infrared photons with an energy smaller than the material bandgaps via a low-efficiency TPA process. The significant avalanche effect with a gain of ∼1300 improves the responsivity, resulting in the record-high responsivity of 88 μA/W. We believe that this work paves the way toward building practical and high-efficiency 2D materials-based infrared photodetectors.

Efficient Frequency Upconversion Photodetection in Heterojunction of InSe and Silicon Photonic Crystal Cavity

“…As shown in Figure 4d, we compare the performance of the InSe/Si-PCC nonlinear photodetector with the previous nonlinear photodetectors based on 2D materials. Our work shows the highest [20] WSe 2 /MoS 2 , [19] MoS 2 , [23] GaSe/InSe, [21] 2D perovskite, [22] and our work (InSe/Si-PCC). The solid red star is the data with a pulsed laser and the open red star is the data with a CW laser.…”

“…A responsivity of 16 μA W −1 was achieved with the CW laser at the power of 1.3 mW, which is competitive with the previous reports with a pulsed laser. [19][20][21][22][23] To exclude the possible origin of the photocurrent from the direct light absorption around the wavelength of 1467 nm by the InSe/Si heterostructure, we carefully examine its absorption behavior by comparing the transmission spectra from a bare Si, a bare InSe and an InSe/Si heterostructure (See Figure S5, Supporting Information). There is no direct light absorption around 1467 nm.…”

“…[21] However, the frequency upconversion responsivity by NLO processes is still below 100 μA W −1 even with a high-energy pulsed laser. [19][20][21][22][23] Here, we realize efficient frequency upconversion photodetection by integrating InSe with a silicon photonic crystal cavity (Si-PCC). Here, 𝜖-InSe is employed.…”

A mixed-dimensional quasi-1D BiSeI nanowire-2D GaSe nanosheet p–n heterojunction for fast response optoelectronic devices

“…Based on this fact, various types of vdW heterojunctions, such as the perovskite junction with tunable work function MXene electrodes, MXene/GaN, MoSe 2 /GaSe, MoS 2 /WSe 2 , GaSe/InSe, and black phosphorus/MoS 2 , have been constructed in order to achieve high performances of optoelectronic devices. 17–24…”

Non-Markovian Hole Excess Noise in Avalanche Amorphous Selenium Thin Films

“…Avalanche photodiodes (APDs) utilize the impact ionization phenomenon with enhanced signal-to-noise ratios (SNRs), to amplify weak signals above the noise floor of readout electronics with applications in photon counting and correlation studies, laser range finding, and medical imaging. − However, the APD gain contributes to its own shot noise component that grows proportionally with avalanche multiplication . This omnipresent shot noise component of the measured noise current source (I N ) can be expressed as , where q is an electronic charge, I inj is the primary injected current into the avalanche junction, ⟨ G ⟩ is the mean multiplication factor of the avalanche process, and ENF is the excess noise factor due to the stochastic nature of the impact ionization multiplication process.…”