SrTiO3 Single Crystal Substrates Research Articles

Solution epitaxy of polarization-gradient ferroelectric oxide films with colossal photovoltaic current

Solution growth of single-crystal ferroelectric oxide films has long been pursued for the low-cost development of high-performance electronic and optoelectronic devices. However, the established principles of vapor-phase epitaxy cannot be directly applied to solution epitaxy, as the interactions between the substrates and the grown materials in solution are quite different. Here, we report the successful epitaxy of single-domain ferroelectric oxide films on Nb-doped SrTiO3 single-crystal substrates by solution reaction at a low temperature of ~200 oC. The epitaxy is mainly driven by an electronic polarization screening effect at the interface between the substrates and the as-grown ferroelectric oxide films, which is realized by the electrons from the doped substrates. Atomic-level characterization reveals a nontrivial polarization gradient throughout the films in a long range up to ~500 nm because of a possible structural transition from the monoclinic phase to the tetragonal phase. This polarization gradient generates an extremely high photovoltaic short-circuit current density of ~2.153 mA/cm2 and open-circuit voltage of ~1.15 V under 375 nm light illumination with power intensity of 500 mW/cm2, corresponding to the highest photoresponsivity of ~4.306×10−3 A/W among all known ferroelectrics. Our results establish a general low-temperature solution route to produce single-crystal gradient films of ferroelectric oxides and thus open the avenue for their broad applications in self-powered photo-detectors, photovoltaic and optoelectronic devices.

Effect of a niobium-doped PZT interfacial layer thickness on the properties of epitaxial PMN-PT thin films

We are reporting on high quality epitaxial thin films of [Pb(Mg1/3Nb2/3)O3]0.67-(PbTiO3)0.33 [PMN-PT (67/33)]. These films were deposited on (001) oriented, vicinal SrTiO3 single crystal substrates, using 1 mol. % niobium-doped Pb(Zr0.52,Ti0.48)O3 (Nb-PZT) as an interfacial layer. The functional properties of the epitaxial PMN-PT (67/33) thin films were investigated as a function of the layer thickness of the Nb-PZT layer. The deposited hetero-structures are perovskite phase pure and fully (001)-oriented. The variation in Nb-PZT interfacial layer thickness results in an increasing trend change of the in-plane lattice parameter of that layer, which in turn causes a decrease in the c/a ratio of the PMN-PT film on top. The most noticeable effect related to this is a decrease in built-in-bias (imprint) voltage. Thus, the built-in bias can be tuned by changing the interfacial layer thickness. The ferroelectric capacitor properties are found to be most stable for the thinnest interfacial layers under a high number (108) of switching cycles.

The role of epitaxial strain on photoconductive performance in LaNiO3 epitaxial thin films

In this work, LaNiO3 epitaxial thin films on (001) single-crystal LaAlO3 and SrTiO3 substrates were deposited by polymer assisted deposition method, respectively. Additionally, LaNiO3 polycrystalline film was coated on ceramic substrate using LaNiO3 powder obtained from precursor solution in polymer assisted deposition. Due to the difference of lattice mismatch between LaNiO3 and single-crystal substrates, LaNiO3 thin films suffer different epitaxial strain, resulting in distortion of NiO6 octahedrons which increases with the intensity of strain. Such phenomena lead to the decrease of the field splitting energy of NiO6 octahedron and the band gap value of LaNiO3, further increasing the charge transition and enhancing the visible-light photoconductivity. The existence of epitaxial strain brings more Ni2+ and adsorbed oxygen into perovskite type LaNiO3, introduces more oxygen vacancy defects, reduces the complex rate of photo induced electron-hole pairs, and thereby improves the photoelectric activity of LaNiO3. This work provides a feasible method to control the structure distortion and photoconductivity effect of all-inorganic perovskite.

The interface of in-situ grown single-layer epitaxial MoS2 on SrTiO3(001) and (111)

SrTiO3 (STO) is a versatile substrate with a high dielectric constant, which may be used in heterostructures with 2D materials, such as MoS2, to induce interesting changes to the electronic structure. STO single crystal substrates have previously been shown to support the growth of well-defined epitaxial single-layer (SL) MoS2 crystals. The STO substrate is already known to renormalize the electronic bandgap of SL MoS2, but the electronic nature of the interface and its dependence on epitaxy are still unclear. Herein, we have investigated an in-situ physical vapor deposition (PVD) method, which could eliminate the need for ambient transfer between substrate preparation, subsequent MoS2 growth and surface characterization. Based on this, we then investigate the structure and epitaxial alignment of pristine SL MoS2 in various surface coverages grown on two STO substrates with a different initial surface lattice, the STO(001)(4 × 2) and STO(111)-(9/5 × 9/5) reconstructed surfaces, respectively. Scanning tunneling microscopy shows that epitaxial alignment of the SL MoS2 is present for both systems, reflected by orientation of MoS2 edges and a distinct moiré pattern visible on the MoS2(0001) basal place. Upon increasing the SL MoS2 coverage, the presence of four distinct rotational domains on the STO(001) substrate, whilst only two on STO(111), is seen to control the possibilities for the formation of coherent MoS2 domains with the same orientation. The presented methodology relies on standard PVD in ultra-high vacuum and it may be extended to other systems to help explore pristine two-dimensional transition metal dichalcogenide/STO systems in general.

Epitaxial Growth of Aurivillius Bi3Fe2Mn2Ox Supercell Thin Films on Silicon

Nanoelectronic devices integrated with functional complex oxides have drawn much attention in recent years. However, due to material and processing compatibility issues, integrating functional complex oxides with Si-based devices is challenging, and success has been limited. As an example, the Bi3Fe2Mn2Ox (BFMO) supercell system, a single-phase layered oxide made by compositing BiFeO3 and BiMnO3, has been studied for much of the past decade for its unusual layered Aurivillius structure and magnetic and ferroelectric properties. However, most of the BFMO thin film growth has been demonstrated on single-crystal oxide substrates such as SrTiO3 and LaAlO3. In this work, we demonstrate that the BFMO layered supercell phase can be integrated on Si with high epitaxial quality using a buffer stack of TiN/SrTiO3/CeO2. Further understanding of the strain-controlled growth of the BFMO supercell phase has allowed such Si integration. Microstructure, magnetic, ferroelectric, and optical properties of the BFMO films on Si have been characterized and compared with those of BFMO on SrTiO3 single-crystal substrates, demonstrating comparable epitaxial quality and physical properties. Integrating multiferroic BFMO oxides on Si demonstrates the potential of layered supercell oxides in practical device applications such as ferroelectric field effect transistors.

Raman spectroscopic characterizations of graphene on oxide substrates for remote epitaxy

Graphene layers placed on SrTiO3 single-crystal substrates, i.e., templates for remote epitaxy of functional oxide membranes, were investigated using temperature-dependent confocal Raman spectroscopy. This approach successfully resolved distinct Raman modes of graphene that are often untraceable in conventional measurements with non-confocal optics due to the strong Raman scattering background of SrTiO3. Information on defects and strain states was obtained for a few graphene/SrTiO3 samples that were synthesized by different techniques. This confocal Raman spectroscopic approach can shed light on the investigation of not only this graphene/SrTiO3 system but also various two-dimensional layered materials whose Raman modes interfere with their substrates.

Physical properties of Cr-doped epitaxial BiFeO3 thin films influenced by ferroelectric domain structures

We investigated the physical properties of Cr-doped epitaxial BiFeO3 (CBFO) thin films influenced by ferroelectric domain structures. The epitaxial CBFO thin films with Cr concentrations of 0, 2, 4, 6, and 8% were deposited on Nb-doped single crystal SrTiO3 substrates by pulsed laser deposition. The epitaxial CBFO thin films with Cr concentrations of 0, 2, and 4% had highly c-oriented crystallinity and the epitaxial CBFO thin films with Cr concentrations of 6% and 8% exhibited mixed crystallinity of c-oriented crystallinity and (101)-oriented crystallinity. The CBFO thin film with a Cr concentration of 4% showed the highest ferroelectric polarization, and the ferroelectric polarizations of the CBFO thin films with a Cr concentration of more than 4% were reduced by the formation of (101)-oriented grains. On the other hand, the piezoelectric properties, leakage current characteristics, and ferromagnetic properties of CBFO thin films were simultaneously improved by increasing the Cr concentration. Terraces indicating layer-by-layer growth were observed on the surface of the CBFO thin films, and the edges of the terraces formed on the surface of the CBFO thin films were blurred when the Cr concentration increased. The ferroelectric domain structures of the CBFO thin films observed with a piezoelectric response microscope changed from a stripe domain structure to a mosaic domain structure when the Cr concentration exceeded 6%.

Magnetoelectric Coupling in Room Temperature Multiferroic Ba2EuFeNb4O15/BaFe12O19 Epitaxial Heterostructures Grown by Laser Ablation.

Multiferroic thin films are a promising class of multifunctional materials, since they allow the integration of multiple functionalities within a single device. In order to overcome the scarcity of single phase multiferroics, it is crucial to develop novel multiferroic heterostructures, combining good ferroelectric and ferromagnetic properties as well as a strong coupling between them. For this purpose, Ba2EuFeNb4O15/BaFe12O19 multiferroic magnetoelectric bilayers have been epitaxially grown on niobium doped SrTiO3 (100) single crystal substrates by pulsed laser deposition. The simultaneous presence of both ferroelectric and magnetic properties-due, respectively, to the Ba2EuFeNb4O15 and BaFe12O19 components-was demonstrated at room temperature, attesting the multiferroic nature of the heterostructure. More interestingly, a strong magnetoelectric coupling was demonstrated (i) by manipulating the ferroelectric properties via an external magnetic field, and conversely, (ii) by tuning the magnetic properties via an external electric field. This strong magnetoelectric coupling shows the high interdependence of both ferroic orders in the Ba2EuFeNb4O15/BaFe12O19 heterostructure, mediated by elastic (epitaxial) strain at the interfaces.

Effect of film thickness on output power of a piezoelectric vibration energy harvester using hydrothermally synthesized (K,Na)NbO3 film

The dependence of the output power of piezoelectric vibration energy harvesters on film thickness was systematically investigated using {100} c -oriented epitaxial (K,Na)NbO3 films prepared on single-crystal SrTiO3 substrates by the hydrothermal deposition technique. First, we measured the vibration energy harvesting properties by a unimorph Pt/(K,Na)NbO3//SrRuO3//SrTiO3 cantilever. Based on the fact that the elastic stiffness of (K,Na)NbO3 is lower than that of SrTiO3 substrate, it can be understood that increasing film thickness leads to decreasing Q m, resulting in the decrease in output power as film thickness increased under the same input acceleration condition. In the next step, these cantilevers were attached to an Al plate having a much larger volume than the Pt/(K,Na)NbO3//SrRuO3//SrTiO3 cantilever. The output power of this type of harvester was more than 400% greater when the film thickness was increased from 3.5 to 22.3 μm due to the almost constant Q m value.

The Magnetic Properties and Magnetocaloric Effect of Pr0.7Sr0.3MnO3 Thin Film Grown on SrTiO3 Substrate

The magnetic behaviors and magnetocaloric effect (MCE) of Pr0.7Sr0.3MnO3 (PSMO-7) film grown on a (001) SrTiO3 single-crystal substrate by a pulsed laser deposition (PLD) were studied in this paper. X-ray diffraction with a high resolution (HRXRD) measurement shows that PSMO-7 film is grown with a (001) single orientation. The magnetic properties and the MCE related to the ferromagnetic (FM) phase transition of the PSMO-7 film are investigated using the temperature dependence of magnetization M(T) and the magnetic field dependence of magnetization M(H). The M(T) data suggest that with decreasing temperatures, the PSMO-7 film goes through the transition from the paramagnetic (PM) state to the FM state at around the Curie temperature (TC). The TC (about 193 K) can be obtained by the linear fit of the Curie law. Magnetic hysteresis loop measurements show that the PSMO-7 film exhibits the FM feature at temperatures of 10, 100, and 150 K (low magnetic hysteresis can be found), while the film reveals the PM feature with the temperature increased up to 200 and/or 300 K. The research results of M(H) data are consistent with the M(T) data. Furthermore, the magnetic entropy change (-ΔSM) of the PSMO-7 film was studied. It was found that the maximum value of (-ΔSM) near TC reaches about 4.7 J/kg·K under the applied field change of 20 kOe, which is comparable to that of metal Gd (-ΔSM of 2.8 J/kg K under 10 kOe), indicating the potential applications of PSMO-7 film in the field of magnetic refrigeration.

Efficient preparation of the inclined La1-xCaxMnO3 films with excellent light-induced transverse thermoelectric performance based on MOCVD process

The efficient preparation of inclined La1-xCaxMnO3 (LCMO) films with excellent light-induced transverse thermoelectric (LITT) performance on c-axis miscut 12° SrTiO3 single crystal substrates is achieved based on the home-designed metal-organic chemical vapor deposition (MOCVD) system. The LCMO films with the thickness of 300 nm are prepared in 1 min, and the preparation efficiency reaches 300 nm/min. Under the radiation of 248 nm pulsed laser with the duration time of 28 ns, the voltage signal of LCMO films shows high sensitivity of 3.13 V/mJ and fast response time of 28 ns, superior to the LITT performance of the reported LCMO under the irradiation of pulsed laser with similar wavelength and duration time. The improvement of LITT performance originates from good electrical conductivity and biaxial texture. Additionally, under the radiation of 900 nm continuous laser, the obvious response voltages can be detected in the LCMO films, and the voltage amplitudes increase linearly with increasing laser power densities. These results demonstrate the application potential of the light detectors composed of LCMO films based on the efficient preparation of MOCVD, and may provide a good prospect for developing low-cost and high-performance light detectors based on the LITT effect.

High-frequency response heat flux sensor based on the transverse thermoelectric effect of inclined La1−xCaxMnO3 films

The heat flux sensors composed of inclined epitaxial La1−xCaxMnO3 (LCMO) films have been fabricated on c-axis miscut SrTiO3 (001) single crystal substrates. Based on the transverse thermoelectric (TTE) effect originated from the anisotropic Seebeck coefficient between ab-plane and c-axis of LCMO films, the obvious response voltages perpendicular to the temperature gradient are detected, and their amplitudes show good linearity with heat fluxes. The sensitivities of heat flux sensors are 8.64, 11.88, 12.66, and 14.25 μV/(kW/m2) for LCMO films with inclined 12°, 18°, 20°, and 24°, respectively. Additionally, the response frequency of the sensor reaches ∼300 kHz at −3 dB, which is comparable with the reported TTE heat flux sensors composed of YBa2Cu3O7-δ. The above results demonstrate the potential of the LCMO-based TTE heat flux sensors in high-frequency heat flux measurement.

Magnetocaloric and Giant Magnetoresistance Effects in La-Ba-Mn-Ti-O Epitaxial Thin Films: Influence of Phase Transition and Magnetic Anisotropy.

Magnetic perovskite films have promising properties for use in energy-efficient spintronic devices and magnetic refrigeration. Here, an epitaxial ferromagnetic La0.67Ba0.33Mn0.95Ti0.05O3 (LBMTO-5) thin film was grown on SrTiO3(001) single crystal substrate by pulsed laser deposition. High-resolution X-ray diffraction proved the high crystallinity of the film with tetragonal symmetry. The magnetic, magnetocaloric and magnetoresistance properties at different directions of the applied magnetic field with respect to the ab plane of the film were investigated. An in-plane uni-axial magnetic anisotropy was evidenced. The LBMTO-5 epilayer exhibits a second-order ferromagnetic-paramagnetic phase transition around 234 K together with a metal-semiconductor transition close to this Curie temperature (TC). The magnetic entropy variation under 5 T induction of a magnetic field applied parallel to the film surface reaches a maximum of 17.27 mJ/cm3 K. The relative cooling power is 1400 mJ/cm3 K (53% of the reference value reported for bulk Gd) for the same applied magnetic field. Giant magnetoresistance of about 82% under 5 T is obtained at a temperature close to TC. Defined as the difference between specific resistivity obtained under 5 T with the current flowing along the magnetic easy axis and the magnetic field oriented transversally to the current, parallel and perpendicular to the sample plane, respectively, the in-plane magneto-resistance anisotropy in 5 T is about 9% near the TC.

Quantitative evaluation of biaxial compressive strain and its impact on proton conduction and diffusion in yttrium-doped barium zirconate epitaxial thin films

Proton-conducting oxides, including 20 mol% yttrium-doped BaZrO3 (BZY20), have attracted considerable attention as electrolytes for environmentally friendly electrochemical cells, such as proton ceramic fuel cells (PCFCs) and proton-conducting solid oxide cells. These oxides exhibit fast proton conduction due to the complex physicochemical phenomena of hydration, chemical lattice expansion, proton migration, proton trapping, and local distortion. Using a proton-conducting oxide as an electrolyte film in electrochemical devices introduces an interface, which thermally and chemically generates mechanical strain. Here, we briefly review the current state of research into proton-conducting oxides in bulk samples and films used in electrochemical devices. We fabricated 18 and 500 nm thick 20 mol% BZY20 epitaxial films on (001) Nb-doped SrTiO3 single-crystal substrates to form a model interface between proton-conductive and non-proton-conductive materials, using pulsed laser deposition, and quantified the mechanical strain, proton concentration, proton conductivity, and diffusivity using thin-film x-ray diffractometry, thermogravimetry, secondary ion mass spectrometry, and AC impedance spectroscopy. Compressive strains of −2.1% and −0.85% were measured for the 18 and 500 nm thick films, respectively, and these strains reduced both the proton conduction and diffusion by five and one orders of magnitude, respectively, at 375 °C. Analysis based on a simple trapping model revealed that the decrease in proton conduction results from the slower diffusion of mobile protons with a negligible change in the proton trapping contribution. The model shows that the high ohmic resistance reported for a high-performance PCFC with a power density of 740 mW cm−2 at 600 °C can be solely explained by the estimated compressive strain in the cells. This study shows that minimizing biaxial compressive strain by appropriate choices of the electrolyte–electrode combination and fabrication process is important for maximizing the performance of electrochemical cells.

Crystallization and Texturing of SrxBa1–xNb2O6 Thin Films Prepared by Aqueous Solution Deposition─An In Situ X-ray Diffraction Study

Aqueous chemical solution deposition (CSD) is an environmentally friendly and highly flexible fabrication route to prepare oxide thin films. Here, we present an aqueous CSD process for ferroelectric SrxBa1–xNb2O6 (SBN) thin films on SrTiO3 (STO) single-crystal substrates. In situ synchrotron X-ray diffraction was employed to study the crystallization of the films during thermal processing with heating rates in the range 0.04–20 °C/s. Three different crystal orientations of SBN were observed based on the heating rate and the orientation of the STO substrates. SBN(001) and SBN(310) orientations were observed on STO(100), while only the SBN(311) orientation was observed on STO(110). The SBN(001) orientation was favored by an ultraslow heating rate of 0.04 °C/s, suggesting that this is the thermodynamic stable orientation. The SBN(310) orientation was kinetically favored at moderate heating rates and also promoted by increasing the Sr content in the film. A high heating rate of 20 °C/s rendered polycrystalline SBN films. It was revealed that nucleation and growth occurred via a classical Volmer–Weber (VW) growth mode and that the SBN grains preferably grow along the c-axis. The present findings demonstrate that control of nucleation and growth is a prerequisite to deposit films with different orientations and textures, which is detrimental for the film properties.

Imprint effect on energy storage performance of Aurivillius Bi3TaTiO9 thin films

We report the imprint effect on the energy storage performance of Bi-layered perovskite (Aurivillius) Bi3TaTiO9 (BTTO) thin films. BTTO thin films were fabricated on single-crystal Nb-doped SrTiO3 substrates using pulsed laser deposition, where the BTTO thin films showed epitaxial c-axis orientation crystal growth with square-shaped grains of terrace structures. The BTTO thin films exhibited ferroelectric hysteresis loops with a remnant polarization of several μC/cm2. An imprint phenomenon in the ferroelectric hysteresis loops occurred by applying the heat treatment of the BTTO thin film. By varying the annealing time (for 5 and 10 min at 550 °C in a vacuum of 10−5 Torr), we elucidated the imprint effect on the energy storage performance. We suggest that oxygen deficiencies induced by the heat treatment cause an imprint effect in the ferroelectric hysteresis loops. As a result, the imprint effect contributed to an increase in the stored energy density and a decrease in the energy loss density in the energy storage performance of the BTTO thin films. Our results demonstrate that the imprint effect can be a critical factor in achieving improved energy efficiency for energy storage performance, which provides new insights into the potential applications of energy storage devices with Bi-layered perovskite BTTO thin films.

Schottky-to-Ohmic switching in ferroelectric memristors based on semiconducting Hf0.93Y0.07O2 thin films

We demonstrate resistive switching and memristive behavior in devices consisting of ultrathin (4.5 nm) semiconducting, epitaxial ferroelectric Hf0.93Y0.07O2 (YHO) films on La0.7Sr0.3MnO3-buffered, Nb-doped SrTiO3 single crystal substrates with Au top electrodes. Unlike the tunneling-driven current–voltage characteristics of ferroelectric tunnel junctions which utilize ultrathin insulating (fully depleted) ferroelectric films, the semiconducting nature of our YHO films, i.e., the presence of free charge carriers introduced by Y doping, results in radically different current–voltage characteristics. Current–voltage measurements indicate a polarization-modulated transition from Schottky-barrier-controlled charge transport to Ohmic conduction in the YHO devices, which results in a large on/off ratio of up to 540. Moreover, voltage pulse train measurements reveal a broad range of accessible resistance states, which indicates the memristive behavior of the devices. Our results represent an important step toward the development of future nonvolatile memory and brain-inspired neuromorphic computing applications based on ultrathin semiconducting ferroelectric films.

High-Efficiency Magnon-Mediated Magnetization Switching in All-Oxide Heterostructures with Perpendicular Magnetic Anisotropy.

The search for efficient approaches to realize local switching of magnetic moments in spintronic devices has attracted extensive attention. One of the most promising approaches is the electrical manipulation of magnetization through electron-mediated spin torque. However, the Joule heat generated via electron motion unavoidably causes substantial energy dissipation and potential damage to spintronic devices. Here, all-oxide heterostructures of SrRuO3 /NiO/SrIrO3 are epitaxially grown on SrTiO3 single-crystal substrates following the order of the ferromagnetic transition metal oxide SrRuO3 with perpendicular magnetic anisotropy, insulating and antiferromagnetic NiO, and metallic transition metal oxide SrIrO3 with strong spin-orbit coupling. It is demonstrated that instead of the electron spin torques, the magnon torques present in the antiferromagnetic NiO layer can directly manipulate the perpendicular magnetization of the ferromagnetic layer. This magnon mechanism may significantly reduce the electron motion-related energy dissipation from electron-mediated spin currents. Interestingly, the threshold current density to generate a sufficient magnon current to manipulate the magnetization is one order of magnitude smaller than that in conventional metallic systems. These findings suggest a route for developing highly efficient all-oxide spintronic devices operated by magnon current.

Dependence of the structure of Bi-2212 superconducting thin film prepared by sol-gel method on different complexing agents

The complexed sol-gel method has unique advantages in the preparation of multi-component functional thin films. In this paper, Bi2212 superconducting thin films were prepared by sol-gel method on SrTiO3(100) single crystal substrates. Glycine and glycolic acid were used as complexing agents. The thermal decomposition processes of the two sols were analyzed by contrasting thermal-thermogravimetric curves. The heat treatment processes of the different complexing agent systems were optimized to obtain films with flatter surface morphology. The phase composition of the intermediate products during the precursor heat treatment was changed by adjusting the conditions of the complexing agent and the acidity of the sol, which expanded the pure phase temperature interval of the final product. The pure phase temperature interval, morphology, surface roughness, and electrical transport properties of Bi2212 superconducting films prepared with different complexing agent sol-gel systems were investigated. When glycolic acid was used as the complexing agent, the Bi-2212 superconducting films showed the widest phase formation temperature zones of 25 K. They also had a smaller surface roughness of 10–15 nm. Other than that, all samples had good epitaxial properties, and electrical transport properties. This work provides a new idea for expanding the phase-forming temperature region of multicomponent functional ceramics. It also shows the promising potential of sol-gel method for preparing multicomponent functional films with high quality surfaces.

Comparative study on laser cleaning SiO2 particle on SrTiO3 and Si surfaces

In this paper, we perform a comparative study, both experimentally and theoretically, on the dry laser cleaning SiO2 particles on the surface of SrTiO3 (STO) and Si single crystal substrates. Firstly, the dependences of the cleaning efficiency on the laser energy density, the pulse number, and the size of SiO2 particles was investigated experimentally. It is found that the laser cleaning threshold decreases with the increase of SiO2 particle size. Furthermore, for the same size of SiO2 particles, the laser cleaning threshold of the STO surface is larger than that of Si. Then, based on the analysis of the interactions among the light field, the particles, and the substrate material, a corrected thermal expansion model with a quantified field enhancement effect was proposed, which provides a good simulation of the dependence of the laser cleaning threshold on the particle size and the substrate. These results further deepen our understanding of the laser dry cleaning, particularly the cleaning process on the oxide surface.