A broad spectral response is highly desirable for radiation detection in modern optoelectronics; however, it still remains a great challenge. Herein, we report a novel ultrabroadband photodetector based on a high-quality tin monoselenide (SnSe) thin film, which is even capable of detecting photons with energies far below its optical band gap. The wafer-size SnSe ultrathin films are epitaxially grown on sodium chloride via the 45° in-plane rotation by employing a sputtering method. The photodetector delivers sensitive detection to ultraviolet–visible–near infrared (UV–Vis–NIR) lights in the photoconductive mode and shows an anomalous response to long-wavelength infrared at room temperature. Under the mid-infrared light of 10.6 μm, the fabricated photodetector exhibits a large photoresponsivity of 0.16 A W–1 with a fast response rate, which is ∼3 orders of magnitude higher than other results. The thermally induced carriers from the photobolometric effect are responsible for the sub-bandgap response. This mechanism is confirmed by a temperature coefficient of resistance of −2.3 to 4.4% K–1 in the film, which is comparable to that of the commercial bolometric detectors. Additionally, the flexible device transferred onto polymer templates further displays high mechanical durability and stability over 200 bending cycles, indicating great potential toward developing wearable optoelectronic devices.

Due to the limited carrier concentration, 2D transition metal dichalcogenides have lower intrinsic dark current, and thus, are widely studied for high performance room photodetection. However, the light‐matter interaction is still unclear, thus tuning the photoexcitation and further manipulating the photodetection is a challenge. Herein, large‐area PtS films are synthesized, and the growth mechanism is investigated. It is demonstrated that PtS has an orthorhombic structure and exhibits the p‐type semiconducting behavior. Then, MoS2/PtS p–n heterojunction is fabricated, and its energy diagram is discussed based on the Kelvin probe force microscopy. The contact potential difference is about 160 mV, which is much larger than previous 2D junctions facilitating the charge separation. Furthermore, the phototransistor based on MoS2/PtS p–n heterojunction is prepared, showing broadband photoresponse from visible to near‐infrared. The manipulation of an external field on photoresponse, detectivity, and rise/fall time are explored and discussed. The responsivity can reach up to 25.43 A W−1, and the detectivity is 8.54 × 1012 Jones. These results indicate that PtS film is a prospective candidate for high‐performance optoelectronic devices and broaden the scope of infrared detection materials.

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.

As a new member in two-dimensional (2D) transition metal dichalcogenides (TMDCs) family, platinum diselenium (PtSe2) has many excellent properties, such as the layer-dependent band gap, high carrier mobility, high photoelectrical coupling, broadband response, etc, thus it shows good promising application in room temperature photodetectors, broadband photodetectors, transistors and other fields. Furthermore, compared with other TMDCs, PtSe2 is chemical inert in ambient, showing nano-devices potential with higher performance and stability. However, up to now, the synthesis and its device applications are in its early stage. This review systematically summarized the state of the art of PtSe2 from its structure, property, synthesis and potential application. Finally, the current challenges and future perspectives are outlined for the applications of 2D PtSe2.

An improved understanding of the origin of the electrical transport mechanism is of importance to the rational design of the highly performance electronic device. However, the complex interfacial environment and...

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