Polarization-Resolved p-Se/n-WS2 Heterojunctions toward Application in Microcomputer System as Multivalued Signal Trigger.

Polarization-sensitive photodetectors based on van der Waals heterojunctions (vdWH) have excellent polarization-resolved optoelectronic properties that can enable the applications in polarized light identification and imaging. With the development of optical microcomputer control systems (OMCS), it is crucial and energy efficient to adopt the self-powered and polarization-resolved signal-generators to optimize the circuit design of OMCS. In this work, the selenium (Se) flakes with in-plane anisotropy and p-type character are grown and incorporated with n-type tungsten disulfide (WS2 ) to construct the type-II vdWH for polarization-sensitive and self-powered photodetectors. Under 405 nm monochrome laser with 1.33 mW cm-2 power density, the photovoltaic device exhibits superior photodetection performance with the photoelectric conversion efficiency (PCE) of 3.6%, the responsivity (R) of 196 mA W-1 and the external quantum efficiency (EQE) of about 60%. The strong in-plane anisotropy of Se crystal structure gives rise to the capability of polarized light detection with anisotropic photocurrent ratio of ≈2.2 under the 405 nm laser (13.71 mW cm-2 ). Benefiting from the well polarization-sensitive and photovoltaic properties, the p-Se/n-WS2 vdWH is successfully applied in the OMCS as multivalued signal trigger. This work develops the new anisotropic vdWH and demonstrates its feasibility for applications in logic circuits and control systems.

Stimuli-Responsive Materials from Ferrocene-Based Organic Small Molecule for Wearable Sensors.

Stimuli-responsive crystals capable of energy conversion have emerged as promising materials for smart sensors, actuators, wearable devices, and robotics. Here, a novel ferrocene-based organic molecule crystal (Fc-Cz) that possesses anisotropic piezoelectric, optical, and mechanical properties is reported. It is demonstrated that the new crystal Fc-Cz can be used as an ultrasensitive piezoelectric material in fabricating strain sensors. The flexible sensor made of crystal Fc-Cz can detect small strains/deformations and motions with a fast response speed. Analysis based on density functional theory (DFT) indicates that an external pressure can affect the dipole moment by changing the molecular configuration of the asymmetric single crystal Fc-Cz in the crystalline state, leading to a change of polarity, and thereby an enhanced dielectric constant. This work demonstrates a new artificial organic small molecule for high-performance tactile sensors, indicating its great potential for developing low-cost flexible wearable sensors.

Tunable Polarity Behavior and Self-Driven Photoswitching in p-WSe2/n-WS2 Heterojunctions.

Van der Waals (vdW) p-n heterojunctions consisting of various 2D layer compounds are fascinating new artificial materials that can possess novel physics and functionalities enabling the next-generation of electronics and optoelectronics devices. Here, it is reported that the WSe2/WS2 p-n heterojunctions perform novel electrical transport properties such as distinct rectifying, ambipolar, and hysteresis characteristics. Intriguingly, the novel tunable polarity transition along a route of n-"anti-bipolar"-p-ambipolar is observed in the WSe2/WS2 heterojunctions owing to the successive work of conducting channels of junctions, p-WSe2 and n-WS2 on the electrical transport of the whole systems. The type-II band alignment obtained from first principle calculations and built-in potential in this vdW heterojunction can also facilitate the efficient electron-hole separation, thus enabling the significant photovoltaic effect and a much enhanced self-driven photoswitching response in this system.

Improving the field-effect performance of Bi2S3 single nanowires by an asymmetric device fabrication.

High-quality Bi2 S3 nanowires are synthesized by chemical vapor deposition and their intrinsic photoresponsive and field-effect characteristics are explored in detail. Among the studied Au-Au, Ag-Ag, and Au-Ag electrode pairs, the device with stepwise band alignment of asymmetric Au-Ag electrodes has the highest mobility. Furthermore, it is shown that light can cause a sevenfold decrease of the on/off ratio. This can be explained by the photoexcited charge carriers that are more beneficial to the increase of Ioff than Ion . The photoresponsive properties of the asymmetric Au-Ag electrode devices were also explored, and the results show a photoconductive gain of seven with a rise time of 2.9 s and a decay time of 1.6 s.

Effect of electrical contact on the performance of Bi2S3 single nanowire photodetectors.

Bi2S3 single-crystalline nanowires are synthesized through a hydrothermal method and then fabricated into single nanowire photodetectors. Due to the different contact barrier between the gold electrode and Bi2S3 nanowires, two kinds of devices with different electrical contacts are obtained and their photoresponsive properties are investigated. The non-ohmic contact devices show larger photocurrent gains and shorter response times than those of ohmic contact devices. Furthermore, the influence of a focused laser on the barrier height between gold and Bi2S3 is explored in both kinds of devices and shows that laser illumination on the Au-Bi2S3 interface can greatly affect the barrier height in non-ohmic contact devices, while keeping it intact in ohmic contact devices. A model based on the surface photovoltage effect is used to explain this phenomenon.

Dual-Junction Field-Effect Transistor with Ultralow Subthreshold Swing Approaching the Theoretical Limit.

Metal-oxide-semiconductor field-effect transistors as basic electronic devices of integrated circuits have been greatly developed and widely used in the past decades. However, as the thickness of the conducting channel decreases, the interface electronic scattering between the gate oxide layer and the channel significantly impacts the performance of the transistor. To address this issue, van der Waals heterojunction field-effect transistors (vdWJFETs) have been proposed using two-dimensional semiconductors, which utilize the built-in electric field at the sharp van der Waals interface to regulate the channel conductance without the need of a complex gate oxide layer. In this study, a novel dual-junction vdWJFET composed of a MoS2 channel and a Te nanosheet gate has been developed. This device achieves an ultralow subthreshold swing (SS) and an extremely low current hysteresis, greatly surpassing the single-junction vdWJFET. In the transistor, the SS decreases from 475.04 to 68.3 mV dec-1, nearly approaching the theoretical limit of 60 mV dec-1 at room temperature. The pinch-off voltage (Vp) decreases from -4.5 to -0.75 V, with a current hysteresis of ∼10 mV and a considerable field-effect mobility (µ) of 36.43 cm2 V-1 s-1. The novel dual-junction vdWJFET provides a new approach to realize a transistor with a theoretical ideal SS and a negligible current hysteresis toward low-power electronic applications.

Thermally Oxidized Memristor and 1T1R Integration for Selector Function and Low-Power Memory.

Resistive switching memories have garnered significant attention due to their high-density integration and rapid in-memory computing beyond von Neumann's architecture. However, significant challenges are posed in practical applications with respect to their manufacturing process complexity, a leakage current of high resistance state (HRS), and the sneak-path current problem that limits their scalability. Here, a mild-temperature thermal oxidation technique for the fabrication of low-power and ultra-steep memristor based on Ag/TiOx/SnOx/SnSe2/Au architecture is developed. Benefiting from a self-assembled oxidation layer and the formation/rupture of oxygen vacancy conductive filaments, the device exhibits an exceptional threshold switching behavior with high switch ratio exceeding 106, low threshold voltage of ≈1 V, long-term retention of >104 s, an ultra-small subthreshold swing of 2.5 mV decade-1 and high air-stability surpassing 4 months. By decreasing temperature, the device undergoes a transition from unipolar volatile to bipolar nonvolatile characteristics, elucidating the role of oxygen vacancies migration on the resistive switching process. Further, the 1T1R structure is established between a memristor and a 2H-MoTe2 transistor by the van der Waals (vdW) stacking approach, achieving the functionality of selector and multi-value memory with lower power consumption. This work provides a mild-thermal oxidation technology for the low-cost production of high-performance memristors toward future in-memory computing applications.

Two-Dimensional GeS/SnSe2 Tunneling Photodiode with Bidirectional Photoresponse and High Polarization Sensitivity.

A two-dimensional (2D) broken-gap (type-III) p-n heterojunction has a unique charge transport mechanism because of nonoverlapping energy bands. In light of this, type-III band alignment can be used in tunneling field-effect transistors (TFETs) and Esaki diodes with tunable operation and low consumption by highlighting the advantages of tunneling mechanisms. In recent years, 2D tunneling photodiodes have gradually attracted attention for novel optoelectronic performance with a combination of strong light-matter interaction and tunable band alignment. However, an in-depth understanding of the tunneling mechanisms should be further investigated, especially for developing electronic and optoelectronic applications. Here, we report a type-III tunneling photodiode based on a 2D multilayered p-GeS/n+-SnSe2 heterostructure, which is first fabricated by the mechanical exfoliation and dry transfer method. Through the Simmons approximation, its various tunneling transport mechanisms dependent on bias and light are demonstrated as the origin of excellent bidirectional photoresponse performance. Moreover, compared to the traditional p-n photodiode, the device enables bidirectional photoresponse capability, including maximum responsivity values of 43 and 8.7 A/W at Vds = 1 and -1 V, respectively, with distinctive photoactive regions from the scanning photocurrent mapping. Noticeably, benefiting from the in-plane anisotropic structure of GeS, the device exhibits an enhanced photocurrent anisotropic ratio of 9, driven by the broader depletion region at Vds = -3 V under 635 nm irradiation. Above all, the results suggest that our designed architecture can be potentially applied to CMOS imaging sensors and polarization-sensitive photodetectors.

Highly Sensitive Broadband Polarized Photodetector Based on the As0.6P0.4/WSe2 Heterostructure toward Imaging and Optical Communication Application.

Polarization-sensitive photodetectors based on two-dimensional anisotropic materials still encounter the issues of narrow spectral coverage and low polarization sensitivity. To address these obstacles, anisotropic As0.6P0.4 with a narrow band gap has been integrated with WSe2 to construct a type-II heterostructure, realizing a high-performance polarization-sensitive photodetector with broad spectral range from 405 to 2200 nm. By operating in photovoltaic mode at zero bias, the device shows a very low dark current of ∼0.02 picoampere, high responsivity of 492 m A/W, and high photoswitching ratio of 6 × 104, yielding a high specific detectivity of 1.4 × 1012 Jones. The strong in-plane anisotropy of As0.6P0.4 endows the device with a capability of polarization-sensitive detection with a high polarization ratio of 6.85 under a bias voltage. As an image sensor and signal receiver, the device shows great potential in imaging and optical communication applications. This work develops an anisotropic vdW heterojunction to realize polarization-sensitive photodetectors with wide spectral coverage, fast response, and high sensitivity, providing a new candidate for potential applications of polarization-resolved electronics and photonics.

Polarization-Sensitive Self-Powered Schottky Photodetector with High Photovoltaic Performance Induced by Geometry-Asymmetric Contacts.

Polarization-sensitive photodetectors have attracted considerable attention owing to their potential application prospects in navigation, optical switching, and communication. However, it remains challenging to develop a facile and effective strategy to simultaneously meet the demands of low power consumption, high performance, and excellent polarization sensitivity. Herein, a series of low-symmetry two-dimensional (2D) ReSe2 Schottky photodetectors with geometry-asymmetric contacts are constructed. These devices exhibit excellent photoelectrical performance and impressive polarization sensitivity in the self-powered mode owing to the difference in the Schottky barrier height induced by the asymmetric contact areas, interfacial states, and thickness difference. Particularly, an outstanding responsivity of 379 mA/W, a decent specific detectivity of 6.8 × 1011 Jones, and a high light on/off ratio (Ilight/Idark) of over 105 under 635 nm light illumination are achieved. Scanning photocurrent mapping (SPCM) measurements further confirm that the ReSe2/drain overlapped region (corresponding to the smaller contact area side) with a higher Schottky barrier height plays a dominant role in the generation of photocurrent. Furthermore, the proposed device displays impressive polarization ratios (PRs) of 3.1 and 3.6 at zero bias under 635 and 808 nm irradiation, respectively. The high-resolution single-pixel imaging capability is also demonstrated. This work reveals the great potential of the ReSe2 Schottky photodetector with geometry-asymmetric contacts for high-performance, self-powered, and polarization-sensitive photodetection.

Polarization- and Gate-Tunable Optoelectronic Reverse in 2D Semimetal/Semiconductor Photovoltaic Heterostructure.

Polarimetric photodetector can acquire higher resolution and more surface information of imaging targets in complex environments due to the identification of light polarization. To date, the existing technologies yet sustain the poor polarization sensitivity (<10), far from market application requirement. Here, the photovoltaic detectors with polarization- and gate-tunable optoelectronic reverse phenomenon are developed based on semimetal 1T'-MoTe2 and ambipolar WSe2 . The device exhibits gate-tunable reverse in rectifying and photovoltaic characters due to the directional inversion of energy band, yielding a wide range of current rectification ratio from 10-2 to 103 and a clear object imaging with 100 × 100 pixels. Acting as a polarimetric photodetector, the polarization ratio (PR) value can reach a steady state value of ≈30, which is compelling among the state-of-the-art 2D-based polarized detectors. The sign reversal of polarization-sensitive photocurrent by varying the light polarization angles is also observed, that can enable the PR value with a potential to cover possible numbers (1→+∞/-∞→-1). This work develops a photovoltaic detector with polarization- and gate-tunable optoelectronic reverse phenomenon, making a significant progress in polarimetric imaging and multifunction integration applications.

2D Free-Standing GeS1-xSex with Composition-Tunable Bandgap for Tailored Polarimetric Optoelectronics.

Germanium-based monochalcogenides (i.e., GeS and GeSe) with desirable properties are promising candidates for the development of next-generation optoelectronic devices. However, they are still stuck with challenges, such as relatively fixed electronic band structure, unconfigurable optoelectronic characteristics, and difficulty in achieving free-standing growth. Herein, it is demonstrated that two-dimensional (2D) free-standing GeS1-xSex (0 ≤ x ≤ 1) nanoplates can be grown by low-pressure rapid physical vapor deposition (LPRPVD), fulfilling a continuously composition-tunable optical bandgap and electronic band structure. By leveraging the synergistic effect of composition-dependent modulation and free-standing growth, GeS1-xSex-based optoelectronic devices exhibit significantly configurable hole mobility from 6.22 × 10-4 to 1.24 cm2V-1s⁻1 and tunable responsivity from 8.6 to 311 A W-1 (635 nm), as x varies from 0 to 1. Furthermore, the polarimetric sensitivity can be tailored from 4.3 (GeS0.29Se0.71) to 1.8 (GeSe) benefiting from alloy engineering. Finally, the tailored imaging capability is also demonstrated to show the application potential of GeS1-xSex alloy nanoplates. This work broadens the functionality of conventional binary materials and motivates the development of tailored polarimetric optoelectronic devices.

Abnormal photocurrent response and enhanced photocatalytic activity induced by charge transfer between WS(2) nanosheets and WO(3) nanoparticles.

Sun trap: Pure WS2 nanosheets are prepared that exhibit excellent photosensitive properties. After functionalization with WO3 nanoparticles, abnormal photocurrent responses, enhanced photocatalytic activity, and induced photoluminescence is observed.

Bi2O2Se Nanowire/MoSe2 Mixed-Dimensional Polarization-Sensitive Photodiode with a Nanoscale Ultrafast-Response Channel.

In recent years, polarization-sensitive photodiodes based on one-dimensional/two-dimensional (1D/2D) van der Waals (vdWs) heterostructures have garnered significant attention due to the high specific surface area, strong orientation degree of 1D structures, and large photo-active area and mechanical flexibility of 2D structures. Therefore, they are applicable in wearable electronics, electrical-driven lasers, image sensing, optical communication, optical switches, etc. Herein, 1D Bi2O2Se nanowires have been successfully synthesized via chemical vapor deposition. Impressively, the strongest Raman vibration modes can be achieved along the short edge (y-axis) of Bi2O2Se nanowires with high crystalline quality, which originate from Se and Bi vacancies. Moreover, the Bi2O2Se/MoSe2 photodiode designed with type-II band alignment demonstrates a high rectification ratio of 103. Intuitively, the photocurrent peaks are mainly distributed in the overlapped region under the self-powered mode and reverse bias, within the wavelength range of 400-nm. The resulting device exhibits excellent optoelectrical performances, including high responsivities (R) and fast response speed of 656 mA/W and 350/380 µs (zero bias) and 17.17 A/W and 100/110 µs (-1 V) under 635 nm illumination, surpassing the majority of reported mixed-dimensional photodiodes. The most significant feature of our photodiode is its highest photocurrent anisotropic ratio of ∼2.2 (-0.8 V) along the long side (x-axis) of Bi2O2Se nanowires under 635 nm illumination. The above results reveal a robust and distinctive correlation between structural defects and polarized orientation for 1D Bi2O2Se nanowires. Furthermore, 1D Bi2O2Se nanowires appear to be a great potential candidate for high-performance rectifiers, polarization-sensitive photodiodes, and phototransistors based on mixed vdWs heterostructures.

Self-Powered Photodetector with High Efficiency and Polarization Sensitivity Enabled by WSe2/Ta2NiSe5/WSe2 van der Waals Dual Heterojunction.

Self-powered photodetectors have triggered widespread attention because of the requirement of Internet of Things (IoT) application and low power consumption. However, it is challenging to simultaneously implement miniaturization, high quantum efficiency, and multifunctionalization. Here, we report a high-efficiency and polarization-sensitive photodetector enabled by two-dimensional (2D) WSe2/Ta2NiSe5/WSe2 van der Waals (vdW) dual heterojunctions (DHJ) along with a sandwich-like electrode pair. On account of enhanced light collection efficiency and two opposite built-in electric fields at the hetero-interfaces, the DHJ device achieves not only a broadband spectral response of 400-1550 nm but outstanding performance under 635 nm light illumination including an ultrahigh external quantum efficiency (EQE) of 85.5%, a pronounced power conversion efficiency (PCE) of 1.9%, and a fast response speed of 420/640 µs, which is much better than that of the WSe2/Ta2NiSe5 single heterojunction (SHJ). Significantly, based on the strong in-plane anisotropy of 2D Ta2NiSe5 nanosheets, the DHJ device shows competitive polarization sensitivities of 13.9 and 14.8 under 635 and 808 nm light, respectively. Furthermore, an excellent self-powered visible imaging capability based on the DHJ device is demonstrated. These results pave a promising platform for realizing self-powered photodetectors with high performance and multifunctionality.

Visible and infrared photodiode based on γ-InSe/Ge van der Waals heterojunction for polarized detection and imaging.

Broadband photodetectors are a category of optoelectronic devices that have important applications in modern communication information. γ-InSe is a newly developed two-dimensional (2D) layered semiconductor with an air-stable and low-symmetry crystal structure that is suitable for polarization-sensitive photodetection. Herein, we report a P-N photodiode based on 3D Ge/2D γ-InSe van der Waals heterojunction (vdWH). A built-in electric field is introduced at the p-Ge/n-InSe interface to suppress the dark current and accelerate the separation of photogenerated carriers. Moreover, the heterojunction belongs to the accumulation mode with a well-designed type-II band arrangement, which is suitable for the fast separation of photogenerated carriers. Driven by these advantages, the device exhibits excellent photovoltaic performance within the detection range of 400 to 1600 nm and shows a double photocurrent peak at around 405 and 1550 nm. In particular, the responsivity (R) is up to 9.78 A W-1 and the specific detectivity (D*) reaches 5.38 × 1011 Jones with a fast response speed of 46/32 µs under a 1550 nm laser. Under blackbody radiation, the room temperature R and D* in the mid-wavelength infrared region are 0.203 A W-1 and 5.6 × 108 Jones, respectively. Moreover, polarization-sensitive light detection from 405-1550 nm was achieved, with the dichroism ratios of 1.44, 3.01, 1.71, 1.41 and 1.34 at 405, 635, 808, 1310 and 1550 nm, respectively. In addition, high-resolution single-pixel imaging capability is demonstrated at visible and near-infrared wavelengths. This work reveals the great potential of the γ-InSe/Ge photodiode for high-performance, broadband, air-stable and polarization-sensitive photodetection.

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

In recent years, two-dimensional (2D) nonlayered Bi2O2Se-based electronics and optoelectronics have drawn enormous attention owing to their high electron mobility, facile synthetic process, stability to the atmosphere, and moderate narrow band gaps. However, 2D Bi2O2Se-based photodetectors typically present large dark current, relatively slow response speed, and persistent photoconductivity effect, limiting further improvement in fast-response imaging sensors and low-consumption broadband detection. Herein, a Bi2O2Se/2H-MoTe2 van der Waals (vdWs) heterostructure obtained from the chemical vapor deposition (CVD) approach and vertical stacking is reported. The proposed type-II staggered band alignment desirable for suppression of dark current and separation of photoinduced carriers is confirmed by density functional theory (DFT) calculations, accompanied by strong interlayer coupling and efficient built-in potential at the junction. Consequently, a stable visible (405 nm) to near-infrared (1310 nm) response capability, a self-driven prominent responsivity (R) of 1.24 A·W-1, and a high specific detectivity (D*) of 3.73 × 1011 Jones under 405 nm are achieved. In particular, R, D*, fill factor, and photoelectrical conversion efficiency (PCE) can be enhanced to 4.96 A·W-1, 3.84 × 1012 Jones, 0.52, and 7.21% at Vg = -60 V through a large band offset originated from the n+-p junction. It is suggested that the present vdWs heterostructure is a promising candidate for logical integrated circuits, image sensors, and low-power consumption detection.

Multifunctional GeAs/WS2 Heterojunctions for Highly Polarization-Sensitive Photodetectors in the Short-Wave Infrared Range.

Polarization-sensitive photodetectors in the infrared range have attracted considerable attention because of their unique and wide application prospects in polarization sensors and remote sensing. However, it is challenging to achieve short-wave infrared polarization detection as most polarization-sensitive photodetectors are based on transition-metal dichalcogenide (TMD) materials with in-plane symmetric crystal structure and sizable band gap (1-2 eV). In this work, we design a type-II GeAs/WS2 heterojunction realizing superior self-driven polarization-sensitive photodetection in the short-wave infrared region. The device shows obvious rectifying behavior with a rectification ratio of 1.5 × 104 in the dark and excellent photoresponse characteristics in a broad spectral range. Accordingly, the high responsivity of 509 mA/W, large on/off ratio of 103, a high EQE of 99.8%, and a high specific detectivity of 1.08 × 1012 Jones are obtained under 635 nm laser irradiation. Taking advantage of the narrow band gap of GeAs with an anisotropic structure, the detection spectral coverage can be extended from the visible to the short-wave infrared range (635-1550 nm). Further, the GeAs/WS2 heterojunction shows high polarization sensitivity with an anisotropic photocurrent ratio of 4.5 and 3.1 at zero bias under 1310 and 1550 nm laser irradiation, respectively, which is much higher than that of reported polarization-sensitive photodetectors in the infrared region. This work provides an effective route using low-symmetry 2D materials with narrow band gap and anisotropic structure to design van der Waals (vdW) heterojunctions, realizing multifunctional optoelectronics for rectifying, photovoltaics, and polarization-sensitive photodetectors with spectral coverage up to 1550 nm.

Low-pressure PVD growth SnS/InSe vertical heterojunctions with type-II band alignment for typical nanoelectronics.

Two-dimensional (2D) polarization-sensitive detection as a new photoelectric application technology is extensively investigated. However, most devices are mainly based on individual anisotropic materials, which suffer from large dark current and relatively low anisotropic ratio, limiting the practical application in polarized imaging system. Herein, we design a van der Waals (vdWs) p-type SnS/n-type InSe vertical heterojunction with proposed type-II band alignment via low-pressure physical vapor deposition (LPPVD) and dry transfer method. The performance compared with the distinctive thickness of anisotropic SnS component was first studied. The fabricated device with a thick (80 nm) SnS nanosheet exhibits a larger rectification ratio exceeding 103. Moreover, the SnS/InSe heterostructure shows a broadband spectral photoresponse from 405 to 1100 nm with a significant photovoltaic effect. Due to efficient photogenerated carrier separation across the wide depletion region at zero bias, the device with thinner (12.4 nm) SnS exhibits trade-off photoresponse performance with a maximum responsivity of 215 mA W-1, an external quantum efficiency of 42.2%, specific detectivity of 1.05 × 1010 Jones, and response time of 8.6/4.2 ms under 635 nm illumination, respectively. In contrast, benefiting from the stronger in-plane anisotropic structure of thinner SnS component, the device delivers a large photocurrent anisotropic ratio of 4.6 under 635 nm illumination in a zigzag manner. Above all, our work provides a new design scheme for multifunctional optoelectronic applications based on thickness-dependent 2D vdWs heterostructures.

A high performance self-powered photodetector based on a 1D Te-2D WS2 mixed-dimensional heterostructure.

One-dimensional (1D)-two-dimensional (2D) van der Waals (vdWs) mixed-dimensional heterostructures with advantages of an atomically sharp interface, high quality and good compatibility have attracted tremendous attention in recent years. Herein, a mixed-dimensional vertical heterostructure is constructed by transferring mechanically exfoliated 2D WS2 nanosheets on epitaxially grown 1D tellurium (Te) microwires. According to the theoretical type-II band alignment, the device exhibits a photovoltaic effect and serves as an excellent self-powered photodetector with a maximum open-circuit voltage (V oc) up to ∼0.2 V. Upon 635 nm light illumination, the photoresponsivity, external quantum efficiency and detectivity of the self-powered photodetector (SPPD) are calculated to be 471 mA W-1, 91% and 1.24 × 1012 Jones, respectively. Moreover, the dark current of the SPPD is highly suppressed to the sub-pA level due to the large lateral built-in electric field, which leads to a high I light/I dark ratio of 104 with a rise time of 25 ms and decay time of 14.7 ms. The abovementioned properties can be further enhanced under a negative bias of -2 V. In brief, the 1D Te-2D WS2 mixed-dimensional heterostructures have great application potential in high performance photodetectors and photovoltaics.