Photothermoelectric SnTe Photodetector with Broad Spectral Response and High On/Off Ratio

Abstract

A broadband photodetector with high performance is highly desirable for the optoelectric and sensing application. Herein, we report a "photo-thermo-electric" (PTE) detector based on an ultrathin SnTe film. The (001)-oriented SnTe films with the wafer size scale are epitaxially grown on the surface of sodium chloride crystals by a scalable sputtering method. Due to the giant PTE effect under laser spot excitation on the asymmetric position between two terminals, a built-in electrical field is produced to drive bulk carriers for a self-powered photodetector, leading to a broad spectral response in the wavelength range from 404 nm to 10.6 μm far beyond the limitation of the energy band gap. Significantly, the photodetector displays a high on/off photoswitching ratio of over 10 5 with a suppressed dark current, which is 4−5 orders of magnitude higher than that of other reported SnTe-based detectors. Under zero external bias, the device yields the highest detectivity of ∼1.3 × 10 10 cm Hz 1/2 W −1 with a corresponding responsivity of ∼3.9 mA W −1 and short rising/falling times of ∼78/84 ms. Furthermore, the photodetector transferred onto the flexible template exhibits excellent mechanical flexibility over 300 bending cycles. These findings offer feasible strategies toward designing and developing low-power-consumption wearable optoelectronics with competitive performance.

Manipulating the Light‐Matter Interaction of PtS/MoS2 p–n Junctions for High Performance Broadband Photodetection

“…For the photodetector, responsivity ( R ) and specific detectivity ( D *) are the key parameters to estimate the detection performance. The value of R indicates the photocurrent generated by excitation per unit power on the effective area and D * is defined as the capacity of the detector to detect weak light signals which could be respectively extracted from the following formulas: [ 41,42 ] where the I p is the photocurrent, I d is the dark current, P opt is the light power, A is the effective device area, and e is the electronic charge. Figure 4d shows the profiles of the responsivity as a function of gate voltage under wavelength of 400 nm with different power density.…”

“…[ 44 ] Another one is originated from thermal effect. [ 41,42 ] Regarding to this study, the photovoltaic effect and thermal effect could be ignored. In other words, θ is the key parameter to distinguish the photoconductive and photogating effects.…”

Emerging Two‐Dimensional Tellurene and Tellurides for Broadband Photodetectors

“…This kind of photodetectors can respond to an ultra-wide spectrum from 404 nm to 10.6 μm while maintaining a low dark current and a high current switching ratio of 10 5 . [73] There remain some drawbacks in respect to improvement of the development of 2D Te photodetectors. For instance, the largearea preparation of simple substance Te is a challenge to address in the future and weak light absorption is one of the major constraints on the photoresponsivity of monolayer Te detectors.…”

Organic/Inorganic Hybrid Boosting Energy Harvesting Based on the Photothermoelectric Effect

“…With the growing energy crisis and environmental pollution, it is of great challenge for researchers to develop the eco-friendly and renewable energy conversion devices. − As we know, the energy conversion efficiency generated by a single photoelectric or thermoelectric material still needs to be improved to date. Recently, photothermoelectric (PTE) conversion has attracted growing attention in the field of new energy due to its capability of converting light to electricity based on photoelectric and thermoelectric effects. , This requires that the corresponding energy materials should have good photoelectric (photo-excited carriers) and thermoelectric (photothermally excited carriers) properties at the same time. However, for a single material, it is difficult to have both good photoelectric and thermoelectric properties simultaneously.…”

“…The excellent photoelectric and thermoelectric properties of tellurium nanowires (Te NWs) have aroused widespread concern in the field of photodetector and thermoelectric energy harvesting. − These attractive properties also imply the possible presence of a good photothermoelectric effect in Te NWs . As an alternative thermoelectric material, an obvious disadvantage of Te NWs is their very low electrical conductivity (σ), despite their considerable Seebeck coefficient ( S ).…”