MoS2/Si Heterojunction with Vertically Standing Layered Structure for Ultrafast,High‐Detectivity,Self‐Driven Visible–Near Infrared Photodetectors

As an interesting layered material, molybdenum disulfide (MoS₂) has been extensively studied in recent years due to its exciting properties. However, the applications of MoS₂ in optoelectronic devices are impeded by the lack of high‐quality p–n junction, low light absorption for mono‐/multilayers, and the difficulty for large‐scale monolayer growth. Here, it is demonstrated that MoS₂ films with vertically standing layered structure can be deposited on silicon substrate with a scalable sputtering method, forming the heterojunction‐type photodetectors. Molecular layers of the MoS₂ films are perpendicular to the substrate, offering high‐speed paths for the separation and transportation of photo‐generated carriers. Owing to the strong light absorption of the relatively thick MoS₂ film and the unique vertically standing layered structure, MoS₂/Si heterojunction photodetectors with unprecedented performance are actualized. The self‐driven MoS₂/Si heterojunction photodetector is sensitive to a broadband wavelength from visible light to near‐infrared light, showing an extremely high detectivity up to ≈10¹³ Jones (Jones = cm Hz^1/2 W^?1), and an ultrafast response speed of ≈3 μs. The performance is significantly better than the photodetectors based on mono‐/multilayer MoS₂ nanosheets. Additionally, the MoS₂/Si photodetectors exhibit excellent stability in air for a month. This work unveils the great potential of MoS₂/Si heterojunction for optoelectronic applications.     

Monolayer MoS2 Growth on Au Foils and On‐Site Domain Boundary Imaging

Controllable synthesis of large domain, high‐quality monolayer MoS₂ is the basic premise both for exploring some fundamental physical issues, and for engineering its applications in nanoelectronics, optoelectronics, etc. Herein, by introducing H₂ as carrier gas, the successful synthesis of large domain monolayer MoS₂ triangular flakes on Au foils, with the edge length approaching to 80 mm is reported. The growth process is proposed to be mediated by two competitive effects with H₂ acting as both a reduction promoter for efficient sulfurization of MoO₃ and an etching reagent of resulting MoS₂ flakes. By using low‐energy electron microscopy/diffraction, the crystal orientations and domain boundaries of MoS₂ flakes directly on Au foils for the first time are further identified. These on‐site and transfer‐free characterizations should shed light on the initial growth and the aggregation of MoS₂ on arbitrary substrates, further guiding the growth toward large domain flakes or monolayer films.     

Memristor Kinetics and Diffusion Characteristics for Mixed Anionic‐Electronic SrTiO3‐δ Bits: The Memristor‐Based Cottrell Analysis Connecting Material to Device Performance

Memristors based on mixed anionic‐electronic conducting oxides are promising devices for future data storage and information technology with applications such as non‐volatile memory or neuromorphic computing. Unlike transistors solely operating on electronic carriers, these memristors rely, in their switch characteristics, on defect kinetics of both oxygen vacancies and electronic carriers through a valence change mechanism. Here, Pt|SrTiO_3‐δ|Pt structures are fabricated as a model material in terms of its mixed defects which show stable resistive switching. To date, experimental proof for memristance is characterized in hysteretic current–voltage profiles; however, the mixed anionic‐electronic defect kinetics that can describe the material characteristics in the dynamic resistive switching are still missing. It is shown that chronoamperometry and bias‐dependent resistive measurements are powerful methods to gain complimentary insights into material‐dependent diffusion characteristics of memristors. For example, capacitive, memristive and limiting currents towards the equilibrium state can successfully be separated. The memristor‐based Cottrell analysis is proposed to study diffusion kinetics for mixed conducting memristor materials. It is found that oxygen diffusion coefficients increase up to 3 × 10^–15 m²s^–1 for applied bias up to 3.8 V for SrTiO_3‐δ memristors. These newly accessible diffusion characteristics allow for improving materials and implicate field strength requirements to optimize operation towards enhanced performance metrics for valence change memristors.     

Lateral and Vertical Morphology Engineering of Low-Symmetry,Weakly-Coupled 2D ReS2

Morphology significantly affects material's electronic, catalytic, and magnetic properties, especially for 2D crystals. Abundant achievements have been made in the morphology engineering of high-symmetry 2D materials, but for the emerging low-symmetry ones, such as ReS₂, both the morphology control technique and comprehension are lacking. Here, the lateral shape and vertical thickness engineering of 2D ReS₂ by tailoring the growth temperature and the substrate symmetry using chemical vapor deposition, is reported. The temperature increase induces an isotropic-to-anisotropic transition of domain shapes, as well as a monotonic decrease of the domain thickness, which promotes the electrocatalytic performance. The substrate rotational symmetry determines the shape anisotropy of polycrystalline ReS₂ monolayers via a diffusion-limited mechanism, leading to highly oriented square, triangular, and strip-like domains synthesized on the fourfold symmetry SrTiO₃ (001), threefold symmetry c-sapphire, and twofold symmetry a-sapphire substrates, respectively. Various stacking configurations in bilayers are unclosed at the atomic scale. Some are predicted to adopt a type-II band alignment with great potential in photovoltaics. The results give insights into the morphological engineering of a unique class of 2D material with low in-plane lattice symmetry and weak interlayer coupling, which are crucial for their high-quality synthesis and industrial applications.     

Oriented Growth of Gold Nanowires on MoS2

Layered 2D materials serve as a new class of substrates for templated synthesis of various nanomaterials even with highly dissimilar crystal structures; thus overcoming the lattice constraints of conventional epitaxial processes. Here, molybdenum disulfide (MoS₂) is used as a prototypical model substrate for oriented growth of in‐plane Au nanowires (NWs) despite the nearly 8% lattice mismatch between MoS₂ and Au. Au NWs on the MoS₂ surface are oriented along three symmetrically equivalent directions within the substrate arising from the strong Au–S binding that templates the oriented growth. The kinetics of the growth process are explored through experiments and modeling. Strong charge transfer is observed between Au NWs and MoS₂, resulting in degenerate p‐doping of MoS₂.     

Engineering Substrate Interactions for High Luminescence Efficiency of Transition‐Metal Dichalcogenide Monolayers

It is demonstrated that the luminescence efficiency of monolayers composed of MoS₂, WS₂, and WSe₂ is significantly limited by the substrate and can be improved by orders of magnitude through substrate engineering. The substrate affects the efficiency mainly through doping the monolayers and facilitating defect‐assisted nonradiative exciton recombinations, while the other substrate effects including straining and dielectric screening play minor roles. The doping may come from the substrate and substrate‐borne water moisture, the latter of which is much stronger than the former for MoS₂ and WS₂ but negligible for WSe₂. Using proper substrates such as mica or hexagonal boron nitride can substantially mitigate the doping effect. The defect‐assisted recombination depends on the interaction between the defect in the monolayer and the substrate. Suspended monolayers, in which the substrate effects are eliminated, may have efficiency up to 40% at room temperatures. The result provides useful guidance for the rational design of atomic‐scale light emission devices.     

Dependence of Photocurrent Enhancements in Quantum Dot (QD)‐Sensitized MoS2 Devices on MoS2 Film Properties

This report demonstrates highly efficient nonradiative energy transfer (NRET) from alloyed CdSeS/ZnS semiconductor nanocrystal quantum dots (QDs) to MoS₂ films of varying layer thicknesses, including pristine monolayers, mixed monolayer/bilayer, polycrystalline bilayers, and bulk‐like thicknesses, with NRET efficiencies of over 90%. Large‐area MoS₂ films are grown on Si/SiO₂ substrates by chemical vapor deposition. Despite the ultrahigh NRET efficiencies there is no distinct increase in the MoS₂ photoluminescence intensity. However, by studying the optoelectronic properties of the MoS₂ devices before and after adding the QD sensitizing layer photocurrent enhancements as large as ≈14‐fold for pristine monolayer devices are observed, with enhancements on the order of ≈2‐fold for MoS₂ devices of mixed monolayer and bilayer thicknesses. For the polycrystalline bilayer and bulk‐like MoS₂ devices there is almost no increase in the photocurrent after adding the QDs. Industrially scalable techniques are specifically utilized to fabricate the samples studied in this report, demonstrating the viability of this hybrid structure for commercial photodetector or light harvesting applications.     

Structural Determinants of the Sign of the Pyroelectric Effect in Quasi‐Amorphous SrTiO3 Films

The magnitude and direction of the permanent electric polarization in the non‐crystalline, polar phase (termed quasi‐amorphous) of SrTiO₃ in Si\SiO₂\Me\SrTiO₃\Me, (Me = Cr or W), Si\SrRuO₃\SrTiO₃, and Si\SrTiO₃ layered structures were investigated. Three potential sources of the polarization which appears after the material is pulled through a temperature gradient were considered: a) contact potential difference; b) a flexoelectric effect due to a strain gradient caused by substrate curvature; and c) a flexoelectric effect due to the thermally induced strain gradient that develops while pulling through the steep temperature gradient. Measurements show that options a) and b) can be eliminated from consideration. In most cases studied in this (Si\SrTiO₃, Si\SiO₂\Me\SrTiO₃\Me, M = Cr or W) and previous works (Si\BaTiO₃, Si\BaZrO₃), the top surface of the quasi‐amorphous phase acquires a negative charge upon heating. However, in Si\SrRuO₃\SrTiO₃ structures the top surface acquires a positive charge upon heating. On the basis of the difference in the measured expansion of the upper and lower surfaces of the SrTiO₃ layer in the presence and absence of SrRuO₃, we contend that the magnitude and direction of the pyroelectric effect are determined by the out‐of‐plane gradient of the in‐plane strain in the SrTiO₃ layer while pulling through the temperature gradient.     

A Coherently Strained Monoclinic [111]PbTiO3 Film Exhibiting Zero Poisson's Ratio State

[111]‐Oriented perovskite oxide films exhibit unique interfacial and symmetry breaking effects, which are promising for novel quantum materials as topological insulators and polar metals. However, due to strong polar mismatch and complex structural reconstructions on (111) surfaces/interfaces, it is still challenging to grow high quality [111] perovskite heterostructures, let alone explore the as‐resultant physical properties. Here, the fabrication of ultrathin PbTiO₃ films grown on a SrTiO₃(111) substrate with atomically defined surfaces, by pulsed laser deposition, is reported. High‐resolution scanning transmission electron microscopy and X‐ray diffraction reveal that the as‐grown [111]PbTiO₃ films are coherent with the substrate and compressively strained along all in‐plane directions. In contrast, the out‐of‐plane lattices are almost unchanged compared with that of bulk PbTiO₃, resulting in a 4% contraction in unit cell volume and a nearly zero Poisson's ratio. Ferroelectric displacement mapping reveals a monoclinic distortion within the compressed [111]PbTiO₃, with a polarization larger than 50 µC cm^?2. The present findings, as further corroborated by phase field simulations and first principle calculations, differ significantly from the common [001]‐oriented films. Fabricating oxide films through [111] epitaxy may facilitate the formation of new phase components and exploration of novel physical properties for future electronic nanodevices.     

Rational Design on Wrinkle-Less Transfer of Transition Metal Dichalcogenide Monolayer by Adjustable Wettability-Assisted Transfer Method

Transfer-induced wrinkles are universal issues when transferring transition metal dichalcogenide (TMDC) monolayer from an as-grown substrate to a target substrate. The undesired transfer-induced wrinkles can mainly be attributed to wettability, which refers to the ability of a liquid to come in contact with a solid surface. Herein, an adjustable wettability-assisted transfer (AWAT) method with different mixtures of transfer media to reduce the density of wrinkles is developed. By manipulating the wettability of the transfer medium with different ratios of alcohol and de-ionized (DI) water, the TMDC monolayer is smoothly attached to the target substrate, thus achieving a wrinkle-less transferred TMDC monolayer. With this method, the density of wrinkles can be decreased by ≈ 15–20% compared with the conventional transfer method by pure DI water. The transferred MoS₂ monolayer with the AWAT method can achieve enhanced carrier mobility from ≈ 20 to ≈ 35 cm² V⁻¹ s⁻¹ in average, which is 30 times larger than that transferred by pure DI water. The AWAT method applied to a WS₂ monolayer onto a SiO₂/p⁺-Si substrate and a MoS₂ monolayer onto a HfO₂/p⁺-Si substrate are demonstrated, which is beneficial in research and applications involving the transfer of TMDC monolayer.     

Preparation and Characterization of Epitaxial Conductive Nb-SrTiO<Subscript>3</Subscript> Thin Films on Si Substrates

Epitaxial Nb-doped SrTiO₃ (001) thin films have been integrated on Si(001) single-crystal substrates with a TiN template layer by radio-frequency (RF) sputtering. The epitaxial growth of Nb-SrTiO₃ was achieved in an Ar environment at a substrate temperature of 540°C. The orientation relationship was determined to be simply cube-on-cube as Nb-SrTiO₃ (001)[110]||TiN(001) [110]||Si(001)[110]. The deposited Nb-SrTiO₃ films show a smooth and featureless surface with roughness below 1 nm. These smooth Nb-doped SrTiO₃/TiN/Si films have a conductivity of 500 S/cm and could be promising electrodes for subsequent ferroelectric thin films.     

High‐Performance Monolayer MoS2 Films at the Wafer Scale by Two‐Step Growth

To realize multifunctional devices at the wafer scale, the growth process of monolayer (ML) 2D semiconductors must meet two key requirements: 1) growth of continuous and homogeneous ML film at the wafer scale and 2) controllable tuning of the properties of the ML film. However, there is still no growth method available that fulfills both of these criteria. Here, the first report is presented on the preparation of continuous and uniform ML MoS₂ films through a two‐step process at the wafer scale. Unlike in previous ML MoS₂ film growth processes, the ML MoS₂ film can be uniformly modulated across the wafer in terms of material structure and composition, exciton state, and electronic transport performance. A significant result is that the high‐quality wafer‐scale ML MoS₂ films realize superior electronic performance compared to reported two‐step‐grown films, and it even matches or exceeds reported ML MoS₂ films prepared by other processes. The transistor performance of the optimized ML film achieves a field effect mobility of 10 to 30 cm² V^?1 s^?1, an on/off current ratio of about 10⁷, and hysteresis as low as 0.4 V.     

6‐Mercaptopurine‐Induced Fluorescence Quenching of Monolayer MoS2 Nanodots: Applications to Glutathione Sensing,Cellular Imaging,and Glutathione‐Stimulated Drug Delivery

Molybdenum disulfide (MoS₂) nanodots (NDs) with sulfur vacancies have been demonstrated to be suitable to conjugate thiolated molecules. However, thiol‐induced fluorescence quenching of MoS₂ NDs has been rarely explored. In this study, 6‐mercaptopurine (6‐MP) serves as an efficient quencher for the fluorescence of monolayer MoS₂ (M‐MoS₂) NDs. 6‐MP molecules are chemically adsorbed at the sulfur vacancy sites of the M‐MoS₂ NDs. The formed complexes trigger the efficient fluorescence quenching of the M‐MoS₂ NDs due to acceptor‐excited photoinduced electron transfer. The presence of glutathione (GSH) efficiently triggers the release of 6‐MP from the M‐MoS₂ NDs, thereby switching on the fluorescence of the M‐MoS₂ NDs. Thus, the 6‐MP‐M‐MoS₂ NDs are implemented as a platform for the sensitive and selective detection of GSH in erythrocytes and live cells. Additionally, thiolated doxorubicin (DOX‐SH)‐loaded M‐MoS₂ NDs (DOX‐SH/M‐MoS₂ NDs) serve as GSH‐responsive nanocarriers for DOX‐SH delivery. In vitro studies reveal that the DOX‐SH/M‐MoS₂ NDs exhibit efficient uptake by HeLa cells and greater cytotoxicity than free DOX‐SH and DOX. In vivo study shows that GSH is capable of triggering the release of DOX‐SH from M‐MoS₂ ND‐based nanomaterials in mice. It is revealed that the DOX‐SH/M‐MoS₂ NDs can be implemented for simultaneous drug delivery and fluorescence imaging.     

Anisotropic Growth of Nonlayered CdS on MoS2 Monolayer for Functional Vertical Heterostructures

2D semiconductors have emerged as a crucial material for use in next‐generation optotelectronics. Similar to microelectronic devices, 2D vertical heterostructures will most likely be the elemental components for future nanoscale electronics and optotelectronics. To date, the components of mostly reported 2D van der Waals heterostructures are restricted to layer crystals. In this work, it is demonstrated that nonlayered semiconductors of CdS can be epitaxially grown on to 2D layered MoS₂ substrate to form a new quasi vertical heterostructure with clean interface by chemical vapor deposition. Photodetectors based on this CdS/MoS₂ heterostructure show broader wavelength response and ≈50‐fold improvement in photoresponsivity, compared to the devices fabricated from MoS₂ monolayer only. This research opens up a way to fabricate a variety of functional quasi heterostructures from nonlayered semiconductors.     

Macroscopic Properties of Restacked,Redox‐Liquid Exfoliated Graphite and Graphite Mimics Produced in Bulk Quantities

The excellent properties exhibited by monolayer graphene have spurred the development of exfoliation techniques using bulk graphite to produce large quantities of pristine monolayer sheets. Development of simple chemistry to exfoliate and intercalate graphite and graphite mimics in large quantities is required for numerous applications. To determine the macroscopic behavior of restacked, exfoliated bulk materials, a systematic approach is presented using a simple, redox‐liquid sonication process along to obtain large quantities of 2D and 3D hexagonally layered graphite, molybdenum disulfide, and boron nitride, which are subsequently characterized to observe chemical and structural changes. For MoS₂ sonicated with the antioxidant sodium bisulfite, results from Raman spectroscopy, X‐ray diffraction, and electron microscopy indicate the presence of distorted phases from different polymorphs, and apparent nanotube structures in the bulk, restacked powder. Furthermore, using thermograviemtric analysis, the antioxidant enhances the resistance to oxidative degradation of MoS₂, upon thermal treatment up to 900 °C. The addition of the ionic antioxidant decreased dispersion stability in non‐polar solvent, suggesting decreased compatibility with non‐polar systems. Using simple chemical methods, the ability to generate tailored multidimensional layered materials with unique macroscopic properties is critical for numerous applications, including electrical devices, reinforced polymer composites, lithium–ion capacitors, and chemical sensing.     

Low Voltage and Ferroelectric 2D Electron Devices Using Lead‐Free BaxSr1‐xTiO3 and MoS2 Channel

Coupling between non‐toxic lead‐free high‐k materials and 2D semiconductors is achieved to develop low voltage field effect transistors (FETs) and ferroelectric non‐volatile memory transistors as well. In fact, low voltage switching ferroelectric memory devices are extremely rare in 2D electronics. Now, both low voltage operation and ferroelectric memory function have been successfully demonstrated in 2D‐like thin MoS₂ channel FET with lead‐free high‐k dielectric Ba_xSr_1‐xTiO₃ (BST) oxides. When the BST surface is coated with a 5.5‐nm‐ultrathin poly(methyl methacrylate) (PMMA)‐brush for improved roughness, the MoS₂ FET with BST (x = 0.5) dielectric results in an extremely low voltage operation at 0.5 V. Moreover, the BST with an increased Ba composition (x = 0.8) induces quite good ferroelectric memory properties despite the existence of the ultrathin PMMA layer, well switching the MoS₂ FET channel states in a non‐volatile manner with a ±3 V low voltage pulse. Since the employed high‐k dielectric and ferroelectric oxides are lead‐free in particular, the approaches for applying high‐k BST gate oxide for 2D MoS₂ FET are not only novel but also practical towards future low voltage nanoelectronics and green technology.     

Constructing Polymorphic Nanodomains in BaTiO3 Films via Epitaxial Symmetry Engineering

Ferroelectric materials owning a polymorphic nanodomain structure usually exhibit colossal susceptibilities to external mechanical, electrical, and thermal stimuli, thus holding huge potential for relevant applications. Despite the success of traditional strategies by means of complex composition design, alternative simple methods such as strain engineering have been intensively sought to achieve a polymorphic nanodomain state in lead‐free, simple‐composition ferroelectric oxides in recent years. Here, a nanodomain configuration with morphed structural phases is realized in an epitaxial BaTiO₃ film grown on a (111)‐oriented SrTiO₃ substrate. Using a combination of experimental and theoretical approaches, it is revealed that a threefold rotational symmetry element enforced by the epitaxial constraint along the [111] direction of BaTiO₃ introduces considerable instability among intrinsic tetragonal, orthorhombic, and rhombohedral phases. Such phase degeneracy induces ultrafine ferroelectric nanodomains (1–10 nm) with low‐angle domain walls, which exhibit significantly enhanced dielectric and piezoelectric responses compared to the (001)‐oriented BaTiO₃ film with uniaxial ferroelectricity. Therefore, the finding highlights the important role of epitaxial symmetry in domain engineering of oxide ferroelectrics and facilitates the development of dielectric capacitors and piezoelectric devices.     

Atomic Vacancy Control and Elemental Substitution in a Monolayer Molybdenum Disulfide for High Performance Optoelectronic Device Arrays

Defect engineering of 2D transition metal dichalcogenides (TMDCs) is essential to modulate their optoelectrical functionalities, but there are only a few reports on defect‐engineered TMDC device arrays. Herein, the atomic vacancy control and elemental substitution in a chemical vapor deposition (CVD)‐grown molybdenum disulfide (MoS₂) monolayer via mild photon irradiation under controlled atmospheres are reported. Raman spectroscopy, photoluminescence, X‐ray, and ultraviolet photoelectron spectroscopy comprehensively demonstrate that the well‐controlled photoactivation delicately modulates the sulfur‐to‐molybdenum ratio as well as the work function of a MoS₂ monolayer. Furthermore, the atomic‐resolution scanning transmission electron microscopy directly confirms that small portions (2–4 at% corresponding to the defect density of 4.6 × 10¹² to 9.2 × 10¹³ cm^?2) of sulfur vacancies and oxygen substituents are generated in the MoS₂ while the overall atomic‐scale structural integrity is well preserved. Electronic and optoelectronic device arrays are also realized using the defect‐engineered CVD‐grown MoS₂, and it is further confirmed that the well‐defined sulfur vacancies and oxygen substituents effectively give rise to the selective n‐ and p‐doping in the MoS₂, respectively, without the trade‐off in device performance. In particular, low‐percentage oxygen‐doped MoS₂ devices show outstanding optoelectrical performance, achieving a detectivity of ≈10¹³ Jones and rise/decay times of 0.62 and 2.94 s, respectively.     

Morphology Engineering in Monolayer MoS2‐WS2 Lateral Heterostructures

In recent years, heterostructures formed in transition metal dichalcogenides (TMDs) have attracted significant attention due to their unique physical properties beyond the individual components. Atomically thin TMD heterostructures, such as MoS₂‐WS₂, MoS₂‐MoSe₂, MoS₂‐WSe₂, and WSe₂‐WS₂, are synthesized so far via chemical vapor deposition (CVD) method. Engineering the morphology of domains including size and shape, however, still remains challenging. Here, a one‐step CVD strategy on the morphology engineering of MoS₂ and WS₂ domains within the monolayer MoS₂‐WS₂ lateral heterostructures through controlling the weight ratio of precursors, MoO₃ and WO₃, as well as tuning the reaction temperature is reported. Not only can the size ratio in terms of area between WS₂ and MoS₂ domains be easily controlled from less than 1 to more than 20, but also the overall heterostructure size can be tuned from several to hundreds of micrometers. Intriguingly, the quantum well structure, a WS₂ stripe embedded in the MoS₂ matrix, is also observed in the as‐synthesized heterostructures, offering opportunities to study quantum confinement effects and quantum well applications. This approach paves the way for the large‐scale fabrication of MoS₂‐WS₂ lateral heterostructures with controllable domain morphology, and shall be readily extended to morphology engineering of other TMD heterostructures.     

Heterojunction of SrTiO3/TiO2 nanotubes with dominant (001) facets: Synthesis,formation mechanism and photoelectrochemical properties

Controllable growth of anatase TiO₂ with dominant high reactive crystal facets has attracted intense interest in the past few years due to their unique structure-dependent properties. In this work, SrTiO₃/TiO₂ heterostructure nanotubes (SrT) arrays films with high reactive dominant (001) facets of anatase TiO₂ were successfully prepared through the part conversion of TiO₂ by a hydrothermal method. Various characterizations were used to investigate the morphologies, crystal phases and chemical compositions of the prepared samples. Structure analyses using X-ray diffraction and a high-resolution transmission electron microscope revealed that, the treatment sequence of hydrothermal reaction and annealing was a crucial influence factor on controlling the growth of preferred orientation of (001) facets of TiO₂ in SrTiO₃/TiO₂ heterojunction, whereas the inverse treatment sequence yielded randomly oriented facets. The formation mechanism of dominant (001) facets of TiO₂ in the heterojunction was related to crystal structures of TiO₂ and SrTiO₃. The heteroepitaxial growth on (001) plane of SrTiO₃ led to dominant (001) facets of anatase TiO₂ attributing to their excellent surface lattices match. The photoelectric performances of pure TiO₂ nanotubes and SrT were investigated by photoluminescence, UV–visible diffuse reflectance, photocurrent and current–voltage response. The semiconductor characteristics of them were studied by electrochemical impedance spectroscopy and Mott–Schottky analysis in detail. The results demonstrated that the heterostructure of SrT not only increased light absorption, but also effectively shifted the Fermi level and promoted charge transfer. Among all the samples, the SrTiO₃/TiO₂ heterojunction prepared by 1 h hydrothermal treatment (1SrT) exhibited the best photoelectrochemical performances due to the synergetic contributions of the high active (001) facets of anatase TiO₂ and the charge transport properties of the heterostructure.