Self-powered Photodetector Research Articles

Bulk photovoltaic effect of ferroelectric Sc-doped GaN thin films toward self-powered light detection

Gallium nitride (GaN), one of the most popular optoelectronic materials in the semiconductor industry, has gained renewed interest as a ferroelectric material when alloyed with scandium. However, the inherent bulk photovoltaic effect (BPE) of GaN-based ferroelectrics has yet to be fully exploited. In this work, a BPE-driven self-powered photodetector based on ferroelectric Sc-doped GaN thin film was fabricated without the usage of a p-n contact. At zero bias, this device features a high responsivity of 45.9 mA/W, a high detectivity of 2.27 × 1011 Jones, a fast response speed of sub-ms-level, a high UV selectivity of 91.3, and an imaging capacity. This work demonstrates the potential of GaN-based ferroelectric thin films in energy-efficient optoelectronic devices.

β-Ga2O3 nanotube arrays for high-performance self-powered ultraviolet photoelectrochemical photodetectors

Self-powered ultraviolet (UV) photodetectors (PDs) are critical for future energy-efficient optoelectronic systems due to their low energy consumption and high sensitivity. In this paper, the vertically aligned β-Ga2O3 nanotube arrays (NTs) have been prepared on GaN/sapphire substrate by the thermal oxidation process combined with the dry etching technology, and applied in the UV photoelectrochemical photodetectors (PEC-PDs) for the first time. Based on the large specific surface area of β-Ga2O3 NTs on GaN/sapphire substrates and the solid/liquid heterojunction, the PEC-PDs exhibit excellent self-powered characteristics under 255 nm (UVA) and 365 nm (UVC) light illumination. Under 255 nm (365 nm) light illumination, the maximum responsivity of 49.9 mA W−1 (32.04 mA W−1) and a high detectivity of 1.58 × 1011 Jones (1.01 × 1011 Jones) were achieved for the β-Ga2O3 NTs photodetectors at 0 V bias. In addition, the device shows a fast rise/decay time of 8/4 ms (4/2 ms), which is superior to the level of the previously reported self-powered UV PEC-PDs. This high-performance PEC-PD has potential applications in next-generation low-energy UV detection systems.

Hierarchical TiO2/SnS2 heterostructure film with enhanced photoelectrochemical performance for self-powered photodetectors

Photoelectrochemical-type photodetectors have attracted extensive attention due to their simple and low-cost fabrication process, without external power sources, high photoresponsivity and fast response speed. Heterostructures can efficiently enhance interfacial carrier transfer and improve the photoelectrochemical performance of the photoelectrode. In this work, two-dimensional TiO2 nanosheets array film exposed {001} facets was firstly synthesized on fluorine-doped tin oxide conductive glass by hydrothermal method. Subsequently, a SnS2 nanoflakes layer was fabricated by chemical bath deposition to form a SnS2/TiO2 composite film considering band alignment and structural design. The morphology, composition and structure of the composites film were characterized. Under simulated sunlight irradiation, the photocurrent density of the SnS2/TiO2 heterojunction photoanode significantly increased to 1.3 mA/cm2, which is approximately 4.7 times and 2.6 times larger than that of the pristine SnS2 and TiO2 film, respectively. Moreover, the photoresponsivity of SnS2/TiO2 composite film reaches up to 12.44 mA/W. The boosted photoelectrochemical performance of SnS2/TiO2 PEC-type photodetectors can be mainly attributed to synergistic effect resulting from efficient light utilization and efficient charge transfer at the interface between SnS2 and TiO2. This work provides new insights for designing two-dimensional optoelectronic and photoelectrochemical devices with improved performance through heterostructure construction.

Self-powered broadband RGB imaging photodetector based on air-stabilized Bi2Te3 nanosheets

Room temperature self-powered broadband (RTSPBD) response photodetectors have received considerable attention and are also very helpful in alleviating today's energy and environmental crisis. Herein, bismuth telluride (Bi2Te3) nanosheets were successfully synthesized and assembled into an RTSPBD photodetector. The Bi2Te3 photodetector exhibits excellent response characteristics: wide spectral range, maximum responsivity (10.254 mA/W, 435 nm), photocurrent density (106 μA/cm2), Ion/Ioff (71, 365 nm, 25 mW/cm2), rise/decay time (τrise = 0.0475 s and τdecay = 0.0468 s) and cycling stability. A superior responsivity from the ultraviolet to infrared (UV-IR) region is observed, which is attributed to the fact that the narrow bandgap topological insulating state of Bi2Te3 provides a fast charge transport channel for electrons generated by the photovoltaic effect. In addition, it was found that these devices have potential applications in red-green-blue (RGB) triple primary color imaging. It is anticipated that this work will provide a great promising candidate material for the design and preparation of high-performance RTSPBD photodetection imaging devices in the future.

Synchronous Regulation Strategy of Pyrrolidinium Thiocyanate Enables Efficient Perovskite Solar Cells and Self-Powered Photodetectors.

Developing inventive approaches tocontrol crystallization and suppress trap defects in perovskite films is crucial for achieving efficient perovskite photovoltaics. Here, a synchronous regulation strategy is developed that involves the infusion of a zwitterionic ionic liquid additive, pyrrolidinium thiocyanate (PySCN), into the perovskite precursor to optimize the subsequent crystallization and defects. PySCN modification not only orchestrates the crystallization process but also deftly addresses trap defects in perovskite films. Within this, SCN- compensates for positively charged defects, while Py+ plays the role of passivating negatively charged defects. Based on the vacuum flash evaporation without anti-solvent, the air-processed perovskite solar cells (PSCs) with PySCN modification can achieve an extraordinary champion efficiency of 22.46% (0.1 cm2) and 21.15% (1.0 cm2) with exceptional stability surpassing 1200 h. Further, the self-powered photodetector goes above and beyond, showcasing an ultra-low dark current of 2.13 × 10-10 A·cm-2, a specific detection rate of 6.12×1013Jones, and an expansive linear dynamic range reaching an astonishing 122.49dB. PySCN modification not only signifies high efficiency but also ushers in a new era for crystallization regulation, promising a transformative impact on the optoelectronic performance of perovskite-based devices.

Self-Powered Photodetectors on the Lateral CsPbBr3/CsPbI3 Perovskite Heterostructure Nanoplates

Self-powered photodetectors have attracted the extensive attention in the past years. Herein, we synthesized the lateral CsPbBr3/CsPbI3 perovskite heterosrtucture nanoplates using anti-solvent solution method and fabricated the self-powered photodetectors by transfer the Au-Au electrodes onto the surface of single CsPbBr3/CsPbI3 nanoplate. Under zero bias, this photodetector showed a reversible switching behavior under turn on/off illumination light with responsivity up to 0.887 mA W−1 and external quantum efficiency of 0.247%, benefiting from the intrinsic built-in electrical potential in the heterosrtuctures. These results enable a significant progress of all-inorganic halide perovskites toward the low-power consumption optoelectronics nanodevices.

Dual-coupling effect enables a high-performance self-powered UV photodetector.

Self-powered ultraviolet photodetectors generally operate by utilizing the built-in electric field within heterojunctions or Schottky junctions. However, the effectiveness of self-powered detection is severely limited by the weak built-in electric field. Hence, advances in modulating the built-in electric field within heterojunctions are crucial for performance breakthroughs. Here, we suggest a method to enhance the built-in electric field by taking advantage of the dual-coupling effect between heterojunction and the self-polarization field of ferroelectrics. Under zero bias, the fabricated AgNWs/TiO2/PZT/GaN device achieves a responsivity of 184.31 mA/W and a specific detectivity of 1.7 × 1013 Jones, with an on/off ratio of 8.2 × 106 and rise/decay times reaching 0.16 ms/0.98 ms, respectively. The outstanding properties are primarily attributed to the substantial self-polarization of PZT induced by the p-GaN and the subsequent enhancement of the built-in electric field of the TiO2/PZT heterojunction. Under UV illumination, the dual coupling of the enhanced heterojunction and the self-polarizing field synergistically boost the photo-generated carrier separation and transport, leading to breakthroughs in ferroelectric-based self-powered photodetectors.

High-Performance Flexible Broadband Photothermoelectric Photodetectors Based on Tellurium Films.

Mid- and far-infrared photodetectors that can operate at room temperature are essential for both civil and military applications. However, the widespread use of mid-to-far-infrared photonic technology faces challenges due to the need for low-temperature cooling of existing commercial semiconductors and the limited optical absorption efficiency of two-dimensional materials. We have utilized the photothermoelectric effect to fabricate a self-powered, broadband, and high-performance photodetector based on a one-dimensional tellurium nanorod array film. The device surpasses energy band gap limitations, functioning even at wavelengths up to approximately 10,600 nm. In particular, the detectivity of the device can reach 4.8 × 109 Jones at 4060 nm under room-temperature conditions, which is an order of magnitude higher than that of commercially available photodetectors. It demonstrates fast response and recovery times of 8.3 and 8.8 ms. Furthermore, the device demonstrates outstanding flexibility withstanding over 300 bending cycles and environmental stability. These results suggest a viable approach for designing and developing high-performance, room-temperature, wearable optoelectronic devices.

A polarization-sensitive, high on/off ratio and self-powered photodetector based on Nb2CT x and Nd2CT x @MoS2

MXene two-dimensional materials have been widely used in energy storage, catalysis, sensing and other fields, Nb2C as a typical two-dimensional MXene material, its exploration in the field of optoelectronics is still in its infancy, especially Nb2C-based photodetectors are still to be developed. This paper demonstrates that two-dimensional films based on few-layer Nb2C have a photoelectric response in the wavelength range from visible to near-infrared. We have found that the light response performance can be easily adjusted by controlling the thickness of the spin-coated film, and that Nb2C photodetectors show great advantages in terms of wide bandwidth, polarization response, high switching ratio, etc. By adjusting the material concentration and sample thickness, the photocurrent can reach up to 330 nA, the switching ratio can reach 410, and the responsivity can reach 8.3 × 10−4 A W−1. In the polarization characteristic test, an extinction ratio of 7.6 can be obtained. By adjusting the content of that doped MoS2 quantum dot, the dark current can reach 7.6 × 10−13 A, and the switching ratio can reach 3 × 105, which can be increased by 700 times. The above results show that the few-layer Nb2C nanosheets can be used as optoelectronic detectors in the visible to near-infrared bands, which further broadens the application prospects of two-dimensional MXene.

Gallium oxide nanocrystals for self-powered deep ultraviolet photodetectors

Zero-dimensional colloidal nanocrystals (NCs) of gamma-phased gallium oxide (γ-Ga2O3) were successfully synthesized using the sol-gel method, resulting in nanocrystals with high crystallinity. Heterojunction photodetectors were then constructed by employing spin-coating technology to deposit γ-Ga2O3 NCs film of varying thicknesses onto p-type GaN substrates. The resulting devices demonstrated self-power capability through a photovoltaic effect when exposed to ultraviolet light illumination. Notably, a device with a 300 nm thick active layer, annealed in 400 °C, exhibited a responsivity of 6.7 × 10–3 A W–1, a detectivity of 3.10 × 1011 Jones, and an external quantum efficiency of 3.2 % under 254 nm light illumination at 0.16 mW cm–2, all without the need for an external power supply. These findings suggest promising practical applications for such photodetectors in single-point imaging systems. This study presents a straightforward and viable approach for developing high-performance and self-powered ultraviolet photodetectors based on zero-dimensional γ-Ga2O3 NCs, thereby opening up possibilities for various photonic systems and applications that do not rely on an external power supply.

Strong polarization sensitivity in a two-dimensional MoS2/WSe2 heterojunction for self-powered photodetection

Polarization-sensitive photodetectors have received considerable attention for their exceptional optoelectronic properties that depend on polarization. It is an excellent method to reduce energy consumption, system's sizes, and cost by constructing self-powered heterojunctions using the two-dimensional materials with asymmetry structure. In this report, we present a self-powered MoS2/WSe2 heterojunction capable of polarized photodetection. The heterojunction exhibits both photovoltaic and pyroelectric effects, which are correlated with the polarized signals. Interestingly, there is a 90° polarization angle between the photovoltaic and pyroelectric effects due to the introduction of in-plane structural polarization. The photovoltaic effect achieves the highest specific detectivity (D*) of about 5 × 1012 Jones when the light polarization is parallel to the in-plane structural polarization. Conversely, the pyroelectric effect dominates and yields the highest D* of about 6 × 109 Jones when the light polarization is perpendicular to the in-plane structural polarization. These findings demonstrate that the specific detectivity of the heterojunction can vary based on the orientation of the light polarization relative to the in-plane structural polarization due to distinct physical mechanisms. Moreover, the self-powered MoS2/WSe2 heterojunction enables simultaneous detection of optical power density and its change rate for polarized light. This study highlights the potential application of two-dimensional heterojunctions for polarization-sensitive self-powered photodetection in the future.

Multifunctional PVDF/CeO2@PDA nanofiber textiles with piezoelectric and piezo-phototronic properties for self-powered piezoelectric sensor and photodetector

In recent years, multifunctional sensors have attracted significant attention due to their ability to detect different types of signals. However, it still remains a challenge to develop flexible materials with multiple sensing functions. Herein, we propose a strategy to fabricate multifunctional flexible textiles (PCP) that can apply piezoelectric and piezo-phototronic effects to self-powered piezoelectric sensor and photodetector (PD) by utilizing the synergistic effect of polydopamine-coated cerium oxide (CeO2@PDA) nanoparticles and poly (vinylidene fluoride) (PVDF). The CeO2@PDA nanoparticles served as local nucleating agents and photosensitizers for the PVDF, enhancing the polar crystalline phase and inducing piezoelectric effect, semiconductor, and optical process coupling in PCP textiles. The piezoelectric sensors consisting of PCP textiles produced extremely high sensitivity (1–10 kPa: 1.27 V/kPa; 10–50 kPa: 0.085 V/kPa; 50–100 kPa: 0.02 V/kPa) and significant electrical output (25.5 V and 0.37 μA). Besides, the piezoelectric sensor had extensive applications including pulse wave measurement, limb motion detection, and active voice recognition. It's especially noteworthy that the PD based on PCP textiles is sensitive for the detecting of sunlight illumination as confirmed by response time (tOn = 2 s and tOff = 4.6 s). Meanwhile, the fabricated self-powered PD showed significant improvement in output current, confirming the realization of the piezo-phototronic effect in PCP textiles. In this work, the low-cost and high-efficiency multifunctional sensing materials were successfully prepared, providing a novel approach for the next generation of self-powered piezoelectric sensors and photodetectors.

Growth Mode Transition in Two-Dimensional GaSe on Three-Dimensional GaN/Sapphire Platform: Implication for Self-Powered Photodetection

Growth Mode Transition in Two-Dimensional GaSe on Three-Dimensional GaN/Sapphire Platform: Implication for Self-Powered Photodetection

Room-temperature synthesis of full-component APbX3 perovskite nanocrystal inks for optoelectronic applications

Lead halide perovskite nanocrystals (PNCs) have received great research interests due to their excellent optoelectronic properties. However, high temperature, inert gas protection and insulating long-chain ligands are used during the conventional hot-injection synthesis of PNCs, which limits their practical applications. In this work, we first develop a simple and scalable polar-solvent-free method for the preparation of full-component APbX3 (A = Cs, methylammonium (MA), formamidinium (FA), X = Cl, Br, I) PNCs under ambient condition. Through an exothermic reaction between butylamine (BA) and propionic acid (PA) short ligands, the PbX2 precursors could be well dissolved without use of any polar solvent. Meanwhile, the relatively lower growth rate of PNCs in our room-temperature reaction enables us to modulate the synthetic procedure to enhance the scalability (40-fold) and achieve large-scale synthesis. The resultant short ligands passivated PNC inks are compatible with varying solution depositing technique like spray coating for large-area film. Finally, we showcase that adopting the as-prepared MAPbI3 PNC inks, a self-powered photodetector is fabricated and shows a high photoresponsivity. These results demonstrate that our ambient-condition synthetic approach can accelerate the preparation of tunable and ready-to-use PNCs towards commercial optoelectronic applications.

Tunable photoresponse properties of CuI/Si self-powered photodetectors through Zn doping engineering

Zn doping engineering was achieved in copper iodide (CuI) films for CuI/Si heterojunction ultraviolet (UV) photodetectors (PDs) by employing a facile solution approach. The morphology, grain sizes and optical properties of CuI films with various Zn2+ doping concentrations are systematically investigated. Our results indicate that an appropriate Zn doping concentration can significantly improve the quality of CuI thin films, leading to an improved photodetection performance, while an excessive amount of Zn dopant can cause poor interface and quality of CuI films. The optimized Zn-doped CuI/Si UV PD exhibited remarkable photodetection performance with a high responsivity of 0.561 A/W at 0 V bias, surpassing all reported CuI-based photodetectors.

Super high-speed self-powered photodetector based on solution-processed transparent p-type amorphous phosphorous-doped SnO film

Super high-speed self-powered photodetector based on solution-processed transparent p-type amorphous phosphorous-doped SnO film

Toward Smart, Flexible, and Omnidirectional Self-Powered Photodetection by an All-Solution-Processed In2O3/Pbl2 Heterojunction.

Amorphous In2O3 film is emerging as a promising oxide semiconductor for next-generation electronics and optoelectronics owing to high mobility and wide band gap. However, the persistent photocurrent phenomenon and high carrier concentration in amorphous In2O3 film are challenging the photodetection performances, resulting in a long response time and low Ilight/Idark ratio. In this work, the In2O3/PbI2 heterojunction is constructed by an all-solution synthesis process to inhibit the persistent photocurrent phenomenon and large dark current. Benefiting from the built-in electric field at the heterojunction interface, the In2O3/PbI2 heterojunction photodetector exhibits excellent self-powered photodetection performances with an ultralow dark current of 10-12 A, a high Ilight/Idark ratio of 104, and fast response times of 0.6/0.6 ms. Furthermore, the entire solution synthesis process and amorphous characteristics enable the fabrication of an In2O3/PbI2 heterojunction photodetector on arbitrary substrates to realize specific functions. When configured onto the polyimide substrate, the In2O3/PbI2 heterojunction photodetector shows excellent mechanical flexibility, bending endurance, and photoresponse stability. When implanted onto the transparent substrate, the In2O3/PbI2 heterojunction photodetector exhibits an outstanding omnidirectional self-powdered photodetection performance and imaging capability. All results pave the way for an all-solution-processed amorphous In2O3 film in advanced high-performance photodetectors.

A Self-Powered Broadband Photodetector with High Photocurrent Based on Ferroelectric Thin Film Using Energy Band Structure Design

Self-powered photodetectors have the advantages of high sensitivity, sustainability, and small size and have become a research hotspot in advanced optoelectronic systems. However, the low output photocurrent density seriously hinders the practical application of ferroelectric self-powered photodetectors. Herein, the high-efficiency photoelectric detection performance of the Bi1-xHoxFeO3 ferroelectric self-powered photodetector is realized by doping Ho. The responsivity (R) and detectivity (D*) can reach 0.0159 A/W and 1.94 × 1011 Jones under monochromatic light with a wavelength of 900 nm. Meanwhile, the R and D* can reach 0.022 A/W and 2.65 × 1011 Jones under sunlight. These excellent photodetection performances are attributed to the high short-circuit current density (Jsc). When the Ho content is 6%, the output photocurrent reaches up to 0.81 mA/cm2. The systematic structure and photo-electric characteristic analysis suggest that the decrease in the band gap leads to the generation of a larger photocurrent while the ferroelectric polarization is reduced slightly. This work provides a new way to obtain high-performance self-powered photodetectors.

Cumulative effect of spectral downshifting, anti-reflection and space-charge region formation in enhancing the spectral response of self-powered silicon photodetectors on sensitisation with CdZnS/ZnS core-shell quantum dots

Despite their ubiquity, Silicon (Si)-based photodetectors face intrinsic limitations that inhibit their performance, especially in the critical ultraviolet (UV) range. Downshifting of high energy photons by employing luminescent quantum dots (QDs) has up to now been the commonest photon harvesting technique in Si photodetectors. This research article describes the monolithic integration of CdZnS/ZnS core-shell QDs with Si photodetectors to make use of the spectral downshifting effect. Silicon detectors sensitised with these QDs have shown remarkably enhanced responsivity and external quantum efficiency over a broad spectral range of 300 - 1100 nm. Apart from the spectral down-shifting process, the anti-reflection effect of the QD film and the formation of a space charge region at the Si-CdZnS/ZnS interface have also contributed to enhanced device performance. The additive effect of spectral downshifting, anti-reflection effects and heterojunction formation has given these QD-sensitized devices enhanced responsivity and EQE values of 345 mA/W and 0.5, markedly higher than the values of 110 mA/W and 0.15 seen in pristine devices. Given the notable enhancement demonstrated without the need for the application of epitaxial techniques, this study may assist in mitigating the inherent limitations of Si photodetectors.

High performance self-powered solar-blind photodetector based on amorphous MgGa2O4/p-Si heterojunction

Self-powered solar-blind photodetectors are extensively implemented in military and industrial applications. Spinel ternary oxide MgGa2O4 with a wide bandgap of 4.92 eV is suitable for solar-blind photodetectors. Optoelectronic integration is a challenging research area, in terms of growing foreign semiconductors on Si substrates. Herein, a solar-blind photodetector based on amorphous MgGa2O4/p-Si heterojunction was fabricated by using RF magnetron sputtering. Under self-powered operation, the device exhibited good performance characteristics, including a high response sensitivity of 11.7 mA/W, a specific detectivity of 7.29 × 1011 Jones, and a fast photoresponse time (τr/τd = 0.200/0.021 s). This work demonstrates that the amorphous MgGa2O4/p-Si heterojunction is a promising approach to realize high-performance self-powered solar-blind photodetectors.