Schottky Barrier Research Articles

Dual‐Polarity Response in Self‐Powered Infrared SnTe Photodetector with Double Symmetric Schottky Junctions

AbstractSelf‐powered photodetectors with dual‐polarity response have great advantages in processing complex light information that is proven to be applied in switchable light imaging, optical communication, and spectral band distinction. Here, a novel strategy for designing self‐powered photodetectors by introducing the double symmetric Schottky junctions at the semiconductor‐metal interfaces is proposed, which guarantees the linear response characteristic and dominates the transfer of photogenerated carriers without external bias. Narrow bandgap semiconductor SnTe is employed as the photosensitive material. The bandgap is characterized to be 126 meV, showing great potential for wide spectrum response. As the consequence of selective excitation of unilateral Schottky junction and switching of electric field polarity, the device obtains a dual‐polarity photoresponse, which can be tuned from −14.8 to 13.5 µV. Moreover, an ultra‐broadband photoresponse from near‐infrared 808 nm to far infrared 10.6 µm is achieved with deep exploration of the working mechanism. The synergistic effect of photo thermoelectricity and photoconductivity created a high photoresponsivity of 0.35 mV W−1 excited by 10.6 µm at room temperature. This work provides a novel design strategy for self‐powered photodetectors with a dual‐polarity powered principle, which can take full advantage of the directivity of the photoresponse to identify optical information.

CVD graphene contacts for lateral heterostructure MoS2 field effect transistors

Intensive research has been carried out on two-dimensional materials, in particular molybdenum disulfide, towards high-performance field effect transistors for integrated circuits1. Fabricating transistors with ohmic contacts is a challenging task due to the formation of a high Schottky barrier that severely limits the performance of the transistors for real-world applications. Graphene-based heterostructures can be used in addition to, or as a substitute for unsuitable metals. In this paper, we present lateral heterostructure transistors made of scalable chemical vapor-deposited molybdenum disulfide and chemical vapor-deposited graphene achieving a low contact resistances of about 9 kΩ·µm and high on/off current ratios of 108. Furthermore, we also present a theoretical model calibrated on our experiments showing further potential for scaling transistors and contact areas into the few nanometers range and the possibility of a substantial performance enhancement by means of layer optimizations that would make transistors promising for use in future logic integrated circuits.

Lattice Strain and Mott-Schottky Effect of the Charge-Asymmetry Pd1Fe Single-Atom Alloy Catalyst for Semi-Hydrogenation of Alkynes with High Efficiency.

The ideal interface design between the metal and substrate is crucial in determining the overall performance of the alkyne semihydrogenation reaction. Single-atom alloys (SAAs) with isolated dispersed active centers are ideal media for the study of reaction effects. Herein, a charge-asymmetry "armor" SAA (named Pd1Fe SAA@PC), which consists of a Pd1Fe alloy core and a semiconducting P-doped C (PC) shell, is rationally designed as an ideal catalyst for the selective hydrogenation of alkynes with high efficiency. Multiple spectroscopic analyses and density functional theory calculations have demonstrated that Pd1Fe SAA@PC is dual-regulated by lattice tensile and Schottky effects, which govern the selectivity and activity of hydrogenation, respectively. (1) The PC shell layer applied an external traction force causing a 1.2% tensile strain inside the Pd1Fe alloy to increase the reaction selectivity. (2) P doping into the C-shell layer realized a transition from a p-type semiconductor to an n-type semiconductor, thereby forming a unique Schottky junction for advancing alkyne semihydrogenation activity. The dual regulation of lattice strain and the Schottky effect ensures the excellent performance of Pd1Fe SAA@PC in the semihydrogenation reaction of phenylethylene, achieving a conversion rate of 99.9% and a selectivity of 98.9% at 4 min. These well-defined interface modulation strategies offer a practical approach for the rational design and performance optimization of semihydrogenation catalysts.

Strong hybridization of Nb2C with MoS2: a way to reduce contact resistance

Abstract 
The hybridization of MXene materials and transition metal dichalcogenides has a significant impact on heterojunction properties. The transport properties and electronic structure of heterojunctions of semiconducting MoS2 and metallic MXene Nb2C were studied by integrating density functional theory with non-equilibrium Green's function theory. The hybridization between Nb2C and MoS2 makes the tunneling barrier between the two layers disappear, which can enhance the electron injection efficiency from the Nb2C to the MoS2. Moreover, the Nb2C/MoS2 heterojunction exhibits a conventional n-type Schottky contact with a barrier height of 0.14 eV, which is significantly lower than the barrier height of 0.29 eV at the Ti/MoS2 junction. These factors result in a field-effect transistor with a low contact resistance of 138 Ω·μm and a higher current of 1.09 mA/μm at a bias voltage of 0.3 V applied between the left and right electrodes. Following the application of gate voltage, the Ion/Ioff ratio reaches 1266.

Significant Enhancement of Electrocaloric Effect in Ferroelectric Polycrystalline Ceramics Through Grain Boundary Barrier Engineering

AbstractA key challenge currently for the new ferroelectric refrigeration with high efficiency and environmental friendliness lies in the urgent demand for ferroelectric materials with huge electrocaloric effects (ECE). Ferroelectric polycrystalline ceramics with high ECE stand out as one of the most promising candidates for electrocaloric cooling applications. However, the grain boundary network, as a barrier for the cross‐transmission of charged carriers, widely exists in electrocaloric polycrystalline ceramics and is often neglected in favor of focusing more on composition regulation and structural design. Herein, a grain boundary barrier engineering is proposed that regulates the Schottky barrier at the grain boundary network in the Ba0.8Zr0.2TiO3 ceramics by a maneuverable annealing process and clarifies its critical role in enhancing the ECE of polycrystalline ceramics. As a result, a substantial enhancement of the EC performance (from 0.68 to 1.63 K at 50 °C and 80 kV cm−1, ≈2.4 times) has been achieved in the annealed Ba0.8Zr0.2TiO3 ceramics with a lower Schottky barrier. The microstructural and electrical characterization reveals that the lower Schottky barrier in the grain boundary network facilitates the domain switching and electronic transition, hence resulting in enhanced polarization response and EC performance.

“Edge in-situ heterogeneous” BiOI based on defect engineering and non-noble metal deposition: Boosting visible-light photocatalytic sterilization

The inherent narrow band gap of bismuth oxyiodide (BiOI) consistently leads to the rapid recombination of photogenerated carriers, significantly constraining its practical utility. To combat this shortcoming, we devise a Bi/BiOI1−x (BB) nanosheet with edge heterostructure. It is modified by the introduction of both iodine defects and in-situ bismuth deposition through high-temperature calcination and solvothermal strategy. Notably, the in-situ deposition of bismuth enhances the visible-light absorption ability of BiOI. And the incorporation of iodine defects initiates a modification in the band position of BiOI, ultimately diminishing the electron-hole recombination rate effectively. More importantly, facilitated by the major work function of bismuth, a Schottky barrier is formed at the BB heterojunction interface, which effectively promotes the separation of photogenerated charges within BB. And the photocurrent intensity of BB is 4 times higher than that of pure BiOI. These ingenious designs result in a significant boost in the generation of reactive oxygen species (ROS) through the accumulation of electrons and holes on the surfaces of both Bi and BiOI1−x. And BB photocatalyst shows an outstanding broad-spectrum bactericidal performance. The antibacterial rates against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) are 88.01% and 90.01%, respectively, which are increased by 80.6% and 83.8% compared with BiOI. Moreover, in vivo experiments provide compelling evidence for the BB photocatalyst’s potential in promoting wound healing. The healing rate after BB treatment has already reached more than 95% on the fifth day. This work offers valuable insights on enhancing the sterilization performance of photocatalysts based on the synergistic effects of defect engineering and non-noble metal deposition.

Vertical Schottky diode on (113) oriented homoepitaxial diamond

Vertical Schottky diodes were fabricated on (113) oriented diamond substrates produced from thick heavily boron doped (NA ∼ 3.5 × 1020 cm−3) diamond layers grown on HPHT-grown synthetic Ib diamond crystals. The p+-substrates were overgrown by a low doped p-epilayer whose surface layer was compensated up to the depth of 0.1 to 0.3 μm. The surface was then oxygen terminated and covered by evaporated Mo/Au Schottky contacts. The bottom ohmic contact to p+-substrate was formed by Ti/Au bi-layer. Current- and capacitance-voltage characteristics of the realized diodes were measured at temperatures ranging from 25 to 180 °C. At room temperature, the realized diodes show high forward current densities JF = 100 A/cm2 and low differential ON-state specific resistance Ron_sp = 3.7 mΩ.cm2 at forward voltage VF = 4 V and a very low leakage (JR < 10−9 A/cm2) in the blocking regime. At 180 °C, forward characteristics significantly improve (JF = 5 kA/cm2, Ron_sp = 0.2 mΩ.cm2 at VF = 4 V) while the blocking characteristics remain almost unchanged (JR = 6 × 10−8 A/cm2 at VR = 4 V). The breakdown electric field is about 3 MV/cm and the rectification ratio keeps at the level of 1011. Characteristics of realized diodes, which are fully comparable to those of Schottky-pn diodes prepared on (111) oriented boron doped diamond, confirm the suitability of (113) orientation for realization of vertical diamond power devices.

Photocatalytic CO2 reduction of CuO-Zn1-xCuxO (ZCO)/Ti3C2Tx MXene heterojunctions with enhanced interfacial charge transfer

Photocatalytic CO2 reduction reaction (CO2RR) synthesis of recycled fuel is a promising pathway to assist the mitigating fossil fuel depletion. Finding efficient and inexpensive high performance CO2RR semiconductor photocatalysts is a giant challenge in the field of photocatalytic reduction. This work constructs the novel-designed interfacial Schottky junction of CuO-Zn1-xCuxO (ZCO)/Ti3C2Tx via electrostatic spinning and electrostatic self-assembly techniques. The catalysts exhibit tight contact heterogeneous interface companies with enhanced CO2 chemisorption capability and proved by various characterizations for efficient carrier separation and migration capacity. The optimized ZCO/Ti3C2Tx nanosheet composites significantly improved their photocatalytic performance. The best samples yielded 5.855 and 2.518 μmol g−1 h−1 of CO and CH4, which are 6 and 1.73 times higher than the conversion of ZCO, respectively, and maintain stability after four cycles without the use of sacrificial agents. In addition, the mechanism and reaction pathways of the photocatalytic process are proposed through In-situ diffuse reflectance Infrared Fourier Transform Spectroscopy (In-situ DRIFTS) and X-ray absorption near edge structure (XANES) analysis. This work provides a new semiconductor/co-catalyst system for the photocatalytic reduction of CO2 and demonstrates that Ti3C2Tx MXene is a hopeful and inexpensive co-catalyst.

Improving ZnO ultraviolet Schottky photodetectors by inserting a MoS2 layer

ZnO Schottky junction photodetectors (PDs) has become a research focus due to their wide application, high-performance and low-cost. However, their development has been limited by the low photo-response. Two-dimensional MoS2 exhibit numerous advantages, including a tunable band gap, a strong exciton effect, and broadband absorption. In this work, we incorporate MoS2 into ZnO thin films using a simple spin-coating method to create Schottky ultraviolet (UV) PDs that show a remarkably increased responsivity (by 885%) and a substantially improved photo-current (by one order of magnitude). Furthermore, they exhibit a relatively low noise equivalent power (5.11×10−13 W) and a high normalized detectivity 2.96×1011 Jones. This outstanding performance can be attributed to the enhanced absorption and efficient charge transfer of ZnO film after introduction of MoS2 layer. In this study, an easy method is presented for creating high-performance ZnO Schottky PDs.

Controllable preparation of TiO2 nanorod arrays for enhanced ultraviolet photoresponse performance of Au/TiO2 Schottky junction

The optical and electrical properties of semiconductors depending on the microstructure are crucial for the application in various optoelectronic devices. TiO2 nanorod arrays (NRs) were prepared by hydrothermal method, and the ultraviolet (UV) photoresponse performance of Au/TiO2 NRs Schottky junction device was studied. The morphology, crystal orientation and filminess of TiO2 NRs were modulated by a facile control strategy employing anhydrous ethanol as stabilizer. With the increase of the amount of anhydrous ethanol, the diameter of TiO2 NR gradually expanded and the length increased rapidly. The anhydrous ethanol promotes the growth of TiO2 NRs preferentially in the [001] direction and decreases the oxygen vacancy in the surface of TiO2 NRs. With 10 mL of anhydrous ethanol added, the device displays a high sensitivity (8.93 A/W) to weak 376 nm UV light (0.18 mW/cm2) at a bias of -1V. The highest carrier concentration, the longest electron lifetime, the lowest interfacial charge transfer resistance and series resistance resulted in the best UV photoresponse. The exploration of dynamics process of photogenerated carriers in Schottky junction can help to improve the performance of optoelectronic devices such as photodetectors and solar cells.

In-situ construct CuInS2/Bi/Bi2MoO6 S-scheme/Schottky dual heterojunctions catalyst for enhanced photocatalytic degradation of diclofenac sodium

In this paper, the S-scheme/Schottky heterojunction photocatalyst (CuInS2/Bi/Bi2MoO6, CIS/Bi/BMO) was successfully constructed via a facile in-situ solvothermal method, aimed at enhancing its photocatalytic performance. The results of the study on the photocatalytic degradation of diclofenac sodium (DCF) under simulated solar light irradiation revealed that the as-prepared composite exhibited remarkable catalytic efficiency in comparison to the pristine Bi2MoO6 and CuInS2. The plasmonic bismuth (Bi) was formed during the solvothermal process. Subsequently, CuInS2 and Bi were grown on the surface of Bi2MoO6 leading to forming CIS/BMO S-scheme heterojunction, along with a Schottky junction between Bi and Bi2MoO6. The use of ethylene glycol as a support was the main reason for the significant improvement in photocatalytic efficiency in the degradation of DCF. Moreover, the probable photocatalytic mechanisms for the degradation of DCF had been proposed based on the active species quenching experiments. The eleven degradation products were detected by HPLC-MS, and the degradation reaction pathway of DCF was deduced. Additionally, the CIS/Bi/BMO photocatalyst exhibited a consistently high removal rate after four cycles. This study proposes a new strategy for designing efficient S-scheme/Schottky heterojunction photocatalysts for solar energy conversion.

Photoelectrochemical properties of self-powered corundum-structured Ga2O3nanorod array/fluorine-doped SnO2photodetectors modulated by precursor concentrations.

Herein, corundum-structured Ga2O3(α-Ga2O3) nanorod array/fluorine-doped SnO2(FTO) structures have been fabricated by hydrothermal and thermal annealing processes with different precursor concentrations from 0.01 M to 0.06 M. The diameter and length of the nanorod arrays are much larger with increasing precursor concentrations due to more nucleation sites and precursor ions participating in the reaction procedures. The optical bandgap decreases from 4.75 eV to 4.47 eV because of the tensile stress relieving with increasing the precursor concentrations. Based on self-powered photoelectrochemical (PEC) photodetectors, the peak responsivity is improved from ~0.33 mA/W for 0.06 M to ~1.51 mA/W for 0.02 M. Schottky junctions can be formed in PEC cells. More photogenerated carriers can be produced in wider depletion region. From Mott-Schottky plots, the depletion regions become much wider with decreasing the precursor concentrations. Therefore, the enhance responsivity is owing to the wider depletion regions. Due to the reduced possibility of photogenerated holes captured by traps ascribed from fewer green and yellow luminescence defects, smaller charge transfer resistance, and shorter transportation route, the decay time becomes much faster through decreasing the precursor concentrations. Compared with the other self-powered α-Ga2O3-nanorod-array-based PEC photodetectors, it shows the fastest response time (decay time of 0.005 s/0.026 s) simply modulated by precursor concentrations for the first time without employing complex precursors, seed layers or special device designs. Compared with other high-responsivity monoclinic Ga2O3(α-Ga2O3) self-powered photodetectors, our devices also show comparable response speed with simple control and design. This work provides the realization of fast-speed self-powered Ga2O3based solar-blind ultraviolet photodetectors by simple modulation processes and design, which is a significant guidance for their applications in warnings, imaging, computing, communication and logic circuit, in the future.

A voltage driven dual-mode MoSe2 photodetector with graphene as van der Waals contact

Abstract Two-dimensional (2D) molybdenum selenide (MoSe2) is promising for developing photodetectors for harvesting lights from UV to near infrared band, while high responsivity and fast response speed are difficult to be simultaneously realized. Herein, we present a dual-mode MoSe2 photodetector with asymmetric electrodes, in which Graphene and Cr metal are utilized as Ohmic and Schottky contacts, respectively. The photodiode possesses a fabulous Schottky characteristic with rectification ratio of ~250 and low dark current of ~40 pA at -1 V. Under forward bias voltage of 1 V, the photodetector works at photoconductive mode with slow response speed (decay time: ~5 minutes) but high responsivity (632 mA/W). However, at reverse bias voltage, the photodetector plays as a photovoltaic type device owing to the Schottky barrier between Cr and MoSe2. Because of the reinforced built-in electric field, the photodetector driven at -5 V shows much faster response speeds (rise time: 1.96 ms; decay time: 755 µs). The study provides a deep understanding of an asymmetric structure MoSe2 photodetctors operated at two modes, which promotes a forward step toward 2D material optoelectronics.&amp;#xD;

Heat-Annealed Zinc Oxide on Flexible Carbon Nanotube Paper and Exposed to Gradient Light to Enhance Its Photoelectric Response.

Buckypaper (BP), a flexible and porous material, exhibits photovoltaic properties when exposed to light. In this study, we employed radio frequency (RF) sputtering of zinc oxide (ZnO) followed by rapid thermal annealing to enhance the photovoltaic response of BP. We investigated the impact of various sputtering parameters, such as the gas flow ratio of argon to oxygen and deposition time, on the morphology, composition, resistivity, and photovoltaic characteristics of ZnO-modified BP. Additionally, the photovoltaic performance of the samples under different illumination modes and wavelengths was compared. It was found that optimal sputtering conditions-argon to oxygen flow ratio of 1:2, deposition time of 20 min, and power of 100 watts-resulted in a ZnO film thickness of approximately 45 nanometers. After annealing at 400 °C for 10 min, the ZnO-modified BP demonstrated a significant increase in photocurrent and photovoltage, along with a reduction in resistivity, compared to unmodified BP. Moreover, under gradient illumination, the ZnO-modified BP exhibited a photovoltage enhancement of 14.70-fold and a photocurrent increase of 13.86-fold, compared to uniform illumination. Under blue light, it showed a higher photovoltaic response than under other colors. The enhancement in photovoltaic response is attributed to the formation of a Schottky junction between ZnO and BP, an increased carrier concentration gradient, and an expanded light absorption spectrum. Our results validate that ZnO sputtering followed by annealing is an effective method for modifying BP for photovoltaic applications such as solar cells and photodetectors.

The influence of lowing the Schottky barrier on the reactive oxygen species formation in Ag@SrBi2Ta2O9 piezocatalyst under ball milling

Loading noble metal nanoparticles on piezoelectric substrates to form the Schottky barrier is believed to be an effective way to promote charge separation and enhance the piezocatalytic performance. The presence of the exceeded Schottky barrier would influence the generation of reactive oxygen species (ROS). However, the detailed correlation between the Schottky barrier height and the type of ROS is not well established. Herein, a type of Aurivillius material, SrBi2Ta2O9 (SBTO) and its composite materials Ag loaded SBTO (Ag@SBTO), were synthesized for different bacteria inactivation and pollutants degradation under ball milling (BM). The results showed that Ag@SBTO3 (0.76 wt% Ag) could lead 7.46 log10 of E. coli K12 inactivation, which was 21.3 times higher than that of SBTO. And Ag@SBTO3 also can achieve about 98.05% of Oxytetracycline degradation, while SBTO showed a better efficiency in Minocycline Hydrochloride and Rhodamine B degradation, the degradation efficiency can reach up to 92.60% and 75.04%, respectively. The variety of catalytic efficiency can be attributed to the different Schottky barrier height and the reduced activation energy of the piezo system when they were subjected to BM effect, which ultimately changed the type of ROS. Our results confirmed that ·OH and ·O2– were the main ROS for SBTO and Ag@SBTO3 during the experiments, respectively, and BM lowering the Schottky barrier of Ag loading piezoelectric material was a facile strategy to generate different ROS for a wide range of applications in water pollution control and drinking water safety.

Gate-controlled spin injection polarity in 2D transistors with Schottky barrier

In 2D semiconductors, the Schottky barrier formed at the metal–semiconductor interface plays a crucial role in controlling electron and spin injection. To explore the spin injection mechanism under gate control, we study MoS2 coupled to ferromagnetic metals. We introduce a spin drift diffusion model which is applicable to the Schottky contact. In this system, the current passing through the Schottky barrier can be larger for the minority spin than for the majority spin due to the tunnel effect. We observe a polarity switching in spin injection with gate voltage variation when the conduction band bottom of the minority spin ferromagnetic metal is closely aligned with the Fermi level. Our results also suggest the spin injection efficiency can be tuned by gate control for half-metals.

High-Performance Schottky-Barrier Field-Effect Transistors Based on Two-Dimensional GaN with Ag or Au Contacts

The performance of two-dimensional (2D) monolayer GaN Schottky barrier field effect transistors (SBFETs) with four different metals (Ag, Au, Al, and Pt) as electrodes were studied by using ab initio simulations. The N-type Schottky contact is formed on Ag-GaN, Au-GaN, and Pt-GaN, characterized by electron Schottky barrier heights (SBH) of 0.6, 0.5, and 0.38 eV, respectively. Whereas, Al-GaN contact formed P-type Schottky contact with hole SBH of 1.42 eV. The 5.1 nm GaN SBFETs with four metal electrodes all could overcome the short-channel effect. Additionally, GaN SBFETs with Ag and Au electrodes have excellent performance, whose ON-currents are 1151.1 μA/μm and 1258.9 μA/μm, respectively. They could satisfy the demands of International Technology Roadmap for Semiconductors for high-performance transistor. Furthermore, research indicates that the device’s current increases with increasing temperature. Notably, under the constant bias and gate voltage, the current is unaffected by temperature variations between the left and right electrodes.

Strain-modulated electronics enabled by surface piezoelectricity

The strain-induced polarization in a piezoelectric semiconductor is an effective strategy to modulate its current transport. However, the piezoelectricity is degraded by the free charges, and the inevitable compromise of piezoelectricity and semiconductivity severely limits the material choice and device performance. We tackle this dilemma by investigating the polarization caused by broken translational symmetry of a material surface. The ubiquitous surface piezoelectricity of solid materials enables the strain-induced polarization change to control the electrical transport effectively in crystals without bulk piezoelectricity. The Schottky barrier is shown to prohibit the bulk charges from screening the surface polarization. The strain engineering of the barrier height leads to an exponential modulation of the current, and an unprecedented gauge factor of 3.10×108 and an on/off ratio of 2.53×105 are demonstrated. The outstanding tunability of current with the synergistic effect of the surface piezoelectricity and metal-semiconductor contact unlocks the device development from various materials.

Sustainable solar-powered hydrogen generation with a silicon nanopillar device with a low carbon footprint

A device system enabling continual hydrogen production under solar light in a water environment is proposed in this study. This system features a self-powered water splitter with a solar harvester from an aluminium-doped zinc oxide/n-type silicon Schottky junction. Thin-film photovoltaic devices are connected in series to reach the reaction potential necessary for the electrolysis of water. Three types of device systems are studied, and their respective hydrogen generation properties are evaluated. The surface passivation effect from only 0.8 nm ultrathin aluminium oxide was found to effectively protect the device surface by withstanding the corrosion of critical solutions for hydrogen generation. In addition, the surface silicon nanopillars create numerical Schottky junctions that can reduce the reaction potential for the electrolysis of DI water from 1.28 V to 0.74 V and achieve a 115 μLh−1cm−2 hydrogen generation rate. Here, a bias-free and simple structural device system is successfully developed and is advantageous for directly converting solar energy into hydrogen among various water systems. The idea of a sustainable solar-powered hydrogen generation system as well as a future low-carbon footprint design meets the principles of the Paris Agreement.

In situ growth of TiO2 on Ti3C2Tx MXene for improved gas-sensing performances

In this study, in situ prepared multiple semiconducting TiO2 in a metallic Ti3C2Tx channel were investigated, which were derived from the Ti3AlC2 MAX phase by oxidation treatments. Several tiny TiO2 particles were in situ formed on the Ti3C2Tx MXene surface when it was heated to 150 °C at ambient conditions. The phase transformation of pristine Ti3C2Tx MXene to oxidized TiO2 was accelerated when the gas-sensing channel was heated to higher temperatures up to 200 °C, yielding a TiO2/Ti3C2Tx composite. The experimental results revealed that the heat-treatment temperature played an important role in the gradual development of the morphology and gas-sensing activity of the TiO2/Ti3C2Tx sensing channel. In particular, the optimal heating temperature of the composite resulted in a good response and recovery time for NO2 molecules. Furthermore, first-principles calculations indicated the good sensing ability of the TiO2/Ti3C2Tx composite for NO2 than for other gases. These results suggest a new strategy for developing gas-sensing ability by forming a Schottky barrier through a simple process.