High-Performance, Polarization-Sensitive, Long-Wave Infrared Photodetection via Photothermoelectric Effect with Asymmetric van der Waals Contacts

Abstract

Long-wavelength infrared (LWIR) photodetection is important for heatseeking technologies, such as thermal imaging, all-weather surveillance, and missile guidance. Among various detection techniques, photothermoelectric (PTE) detectors are promising in that they can realize ultra-broadband photodetection at room temperature without an external power supply. However, their performance in terms of speed, responsivity, and noise level in the LWIR regime still needs further improvement. Here, we demonstrated a high-performance PTE photodetector based on low-symmetry palladium selenide (PdSe 2 ) with asymmetric van der Waals contacts. The temperature gradient induced by asymmetric van der Waals contacts even under global illumination drives carrier diffusion to produce a photovoltage via the PTE effect. A responsivity of over 13 V/W, a response time of ∼50 μs, and a noise equivalent power of less than 7 nW/Hz 1/2 are obtained in the 4.6−10.5 μm regime at room temperature. Furthermore, due to the anisotropic absorption of PdSe 2 , the detector exhibits a linear polarization angle sensitive response with an anisotropy ratio of 2.06 at 4.6 μm and 1.21 at 10.5 μm, respectively. Our proposed device architecture provides an alternative strategy to design high-performance photodetectors in the LWIR regime by utilizing van der Waals layered materials.

On-chip mid-infrared photothermoelectric detectors for full-Stokes detection

“…The high SoP-dependent optical absorption directly leads to a polarization-resolved PTE response in the detector integrated with chiral plasmonic metamaterials 9 , 39 . To experimentally demonstrate this, we first fabricated devices using different 2D thermoelectric materials including graphene (Gr) 40 , 41 , black phosphrous (BP) 13 , and palladium selenide (PdSe 2 ) 42 , 43 nanoflakes as the active thermoelectric materials according to the configuration shown in Fig. 1f .…”

Fully Depleted Self‐Aligned Heterosandwiched Van Der Waals Photodetectors

“…for uncooled MWIR detection [8][9][10][11][12][13][14][15][16] with a thinner absorber and lower thermal noise. [17] In particular, 2D layered crystals without dangling bonds can reduce the noise generated by generation-recombination and avoid problems such as lattice mismatch.…”

“…Therefore, developing next‐generation MWIR photodetectors that are suitable for chip‐scale integration and operation at room temperature is urgent. Fortunately, the discovery of 2D narrow‐bandgap semiconductors such as black phosphorus (BP), Te, PdSe 2 , and PtSe 2 , with high carrier mobility and strong infrared light absorption has opened up new opportunities for uncooled MWIR detection [ 8–16 ] with a thinner absorber and lower thermal noise. [ 17 ] In particular, 2D layered crystals without dangling bonds can reduce the noise generated by generation‐recombination and avoid problems such as lattice mismatch.…”

SrTiO3/CuNi‐Heterostructure‐Based Thermopile for Sensitive Human Radiation Detection and Noncontact Human–Machine Interaction

“…[44] the temperature gradient. [26,41] In order to obtain a net photoresponse, the key point is to introduce an asymmetric configuration, which is often realized by employing asymmetric electrodes with different work functions, [25,26] thermal conductivities [19,23] or optical absorption. [42,43] In the case of the macro scopic SrTiO 3−x /CuNi composite, the asymmetric heat dissipation channel was designed to maximize the effective optical absorption area.…”