CN110246958B - Method for improving photoelectric response of BFO/ZnO heterojunction device - Google Patents
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Abstract
The invention provides a method for improving photoelectric response of a BFO/ZnO heterojunction device, wherein the BFO/ZnO heterojunction device sequentially comprises a bottom electrode, a BFO ferroelectric film, a ZnO seed crystal layer, a ZnO nanowire array and an upper electrode from bottom to top.
Description
Technical Field
The invention belongs to the field of ferroelectric semiconductor heterojunction devices, and particularly relates to a method for improving photoelectric response of a BFO/ZnO heterojunction device.
Background
Based on BiFeO3The heterojunction formed by the (BFO) bismuth ferrite thin film and the ZnO nanowire is widely studied due to its potential ferroelectric, piezoelectric and photoelectric effects. Existing research has shown that the photoelectric effect can be enhanced by using a ZnO film/nanowire or a heterojunction formed with a BFO film, because ZnO may contact with BFO to form a heterojunction, and a built-in electric field generated at an interface of the heterojunction contributes to separation and transport of photo-generated electron-hole pairs. However, how to further improve the photoelectric response of the BFO/ZnO heterojunction device is an urgent problem to be solved in the field.
Disclosure of Invention
The invention prepares a BFO/ZnO nanowire heterojunction device based on a ferroelectric film, and finally achieves the purpose of improving the photoelectric response of the heterojunction by applying compressive strain to the BFO/ZnO heterojunction to adjust the interface energy band structure and the transport of photon-generated carriers in a junction region.
A ferroelectric film BFO/ZnO nanowire-based heterojunction device comprises a bottom electrode, a BFO ferroelectric film 3, a ZnO seed crystal layer 4, a ZnO nanowire array 5 and an upper electrode 6 from bottom to top in sequence as shown in figure 1. The bottom electrode is FTO conductive glass and comprises a glass layer 1 and an FTO layer 2. The upper electrode 6 is an ITO electrode layer.
A preparation method of a BFO/ZnO nanowire heterojunction device based on a ferroelectric film is characterized in that a BFO ferroelectric film 3 is prepared on FTO conductive glass by adopting a sol-gel spin coating method, a ZnO seed crystal layer 4 is prepared on the BFO ferroelectric film by utilizing magnetron sputtering, a ZnO nanowire array 5 vertically grows upwards by utilizing a hydrothermal method, and finally an ITO transparent electrode is deposited by utilizing magnetron sputtering.
The length of the nano-wire in the ZnO nano-wire array 5 is 5-10 μm, and the diameter of the nano-wire is 160-200 nm. The ZnO nanowire grows along the c-axis direction. The crystal orientation, overlength, overthickness or overthinness of the ZnO nanowire can seriously affect the coupling effect of stress and piezoelectric photoelectron. Only the ZnO nanowire array within the limited range can promote the separation of carriers in the BFO/ZnO heterojunction junction region through the piezoelectric potential generated when the nanowires are strained, and the photoelectric performance of the heterojunction device is enhanced.
The ZnO nanowire is prepared and synthesized by a two-step hydrothermal method. Firstly, depositing a ZnO seed crystal layer by using a radio frequency magnetron sputtering method, and vertically growing a ZnO nanowire array along the c-axis direction of the ZnO seed crystal by using a hydrothermal method after the ZnO seed crystal layer is prepared.
And applying a compressive acting force on the c-axis top end of the ZnO nanowire to enable the nanowire to generate strain on the BFO/ZnO heterojunction device, and promoting the separation of carriers in a BFO/ZnO heterojunction junction region through the piezoelectric potential generated when the nanowire generates strain to enhance the photoelectric property of the heterojunction device. Under the dark condition, the dark current of the BFO/ZnO heterojunction device is continuously increased along with the increase of the compressive strain, and after illumination is applied, the photocurrent shows the same change trend as the dark current along with the increase of the compressive strain. The short-circuit current under illumination also increases along with the increase of the compressive strain, namely 0.7458mA/cm under the non-strain condition2Increased to 0.9030mA/cm with increasing strain to-1.3%2The increase is 21%, the open-circuit voltage is slightly reduced, the initial-0.31V is reduced to-0.30V after being subjected to-1.3% pressure strain, but the voltage is too weak relative to the increase of short-circuit current, so that the BFO/ZnO is externally addedThe compressive strain generated after the compressive acting force plays a role in enhancing the photoelectric conversion efficiency of the whole heterojunction device.
The invention has the beneficial effects that:
the BFO/ZnO nanowire heterojunction device is characterized in that a compressive acting force is applied to the top end of a c-axis of a ZnO nanowire of the BFO/ZnO heterojunction device to enable the nanowire to be strained, and the separation of carriers in a junction area of the BFO/ZnO heterojunction is promoted through a piezoelectric potential generated when the nanowire is strained, so that the photoelectric property of the heterojunction device is enhanced, and the short-circuit voltage of the heterojunction is 0.7458mA/cm2Increased to 0.9030mA/cm2The device is now subjected to a compressive strain of-1.3%. The BFO/ZnO heterojunction device has certain potential in the novel piezoelectric-photoelectric energy conversion and sensor direction.
Secondly, the BFO/ZnO heterojunction structure is prepared by using two-step hydrothermal growth of ZnO nanowires on the BFO film, so that the photoelectric property is remarkably improved compared with that of the BFO film, the wavelength is 405nm, and the power density is 200mW/cm2Under the irradiation of blue and violet light, the short-circuit current is improved by 6 times, and the open-circuit voltage is increased by 1.5 times.
Drawings
FIG. 1 is a structural schematic diagram of a BFO/ZnO heterojunction device.
Fig. 2 is an SEM image of the BFO film on the FTO conductive glass, in which fig. 2(a) visually reflects that the BFO film has a uniform and dense surface and good flatness, and the sectional SEM image of the BFO film in fig. 2(b) shows that the film thickness is 522nm and the boundary with the FTO conductive layer is clear, so we judge that the BFO film prepared by the sol-gel spin coating method has good quality.
FIG. 3 is an SEM image of a BFO/ZnO heterojunction structure. Wherein FIG. 3(a) shows the surface profile and FIG. 3(b) shows the cross-sectional profile
FIG. 4 is an XRD analysis of the BFO thin film and the BFO/ZnO heterojunction bilayer film, wherein FIG. 4(a) is an XRD pattern of the BFO thin film and FIG. 4(b) is an XRD pattern of the BFO/ZnO heterojunction structure.
Figure 5 is an out-of-plane PFM phase diagram of a BFO film.
Fig. 6 shows that the phase curve and amplitude variation measured by PFM are typical characteristics of ferroelectric materials. FIGS. 6(a) and 6(b) are graphs of the phase and amplitude, respectively, of the BFO film as a function of applied bias.
FIG. 7 is a BFO film and ZnO nanowire ultraviolet-visible spectrophotometer test spectrum. In which fig. 7(a) transmission spectrum, 7(b) absorption spectrum, and 7(c) band gap fit.
FIG. 8 is a photoelectric characteristic curve of an ITO/BFO/FTO device and an ITO/ZnO NWs/BFO/FTO heterojunction device under 405nm blue-violet light irradiation. The optical power density is 200mW/cm2. 8(a) J-V curve of BFO film in dark state and illumination, 8(b) J-V curve of BFO film and BFO/ZnO heterojunction in illumination condition, 8(c) J-T curve of BFO film and BFO/ZnO heterojunction in zero bias voltage, and 8(d) response and recovery time of single on/off cycle.
FIG. 9 is a photoelectric characteristic curve of the BFO/ZnO heterojunction device under compressive stress in a dark state and under illumination conditions. Wherein 9(a) the J-V curve of the BFO/ZnO heterojunction under different strain conditions in a dark state, 9(b) the J-V curve of the BFO/ZnO heterojunction under different strain conditions under illumination, 9(c) a partial enlarged view of the change of short-circuit current (upper) and open-circuit voltage (lower) when the BFO/ZnO heterojunction is subjected to different strains under illumination, and 9(d) the photoelectric response curve of the BFO/ZnO heterojunction under different strains
FIG. 10 is a schematic diagram of the change in energy band of a BFO/ZnO heterojunction under compressive strain.
Detailed Description
The present invention is described in further detail below by way of implementation but is not limited to the present invention, and various modifications and improvements can be made in accordance with the basic idea of the present invention without departing from the scope of the invention.
Examples
A ferroelectric film BFO/ZnO nanowire-based heterojunction device comprises a bottom electrode, a BFO ferroelectric film 3, a ZnO seed crystal layer 4, a ZnO nanowire array 5 and an upper electrode 6 from bottom to top in sequence as shown in figure 1. The bottom electrode is FTO conductive glass and comprises a glass layer 1 and an FTO layer 2. The upper electrode 6 is an ITO electrode layer. The preparation method comprises the following steps.
And step 1, preparing BFO precursor liquid.
1.2143g of iron nitrate nonahydrate [ Fe (NO3) 3.9H 2O ] weighed in a volume of 5ml of ethylene glycol monomethyl ether were dissolved and stirred at room temperature using a magnetic stirrer at a rotational speed of 600r/min until completely dissolved, after which 1.5998g of bismuth nitrate pentahydrate [ Bi (NO3) 3.5H 2O ] were added in an excess of 10% in view of volatilization of bismuth element. And simultaneously adding 3ml of glacial acetic acid and 2ml of acetic anhydride as dehydrating agents into the solution, continuously stirring for 30min, adding 100 mu L of ethanolamine to adjust the viscosity of the solution after the medicine is completely dissolved and dispersed in the solvent, continuously stirring at room temperature for 12h, and aging for 24h to obtain 0.3mol/L precursor solution.
And 2, preparing the BFO film.
The BFO ferroelectric film is prepared by a spin-coating method. The substrate used was FTO conductive glass with a gauge size of 15mm × 15mm × 2 mm. And (3) before spin coating, ultrasonically cleaning the FTO glass by using deionized water, acetone and absolute ethyl alcohol in sequence, circularly cleaning twice, and blow-drying by using a nitrogen gun. Fixing the FTO substrate on a spin coater, dropping a proper amount of precursor on the conductive glass, and then rotating the spin coater at a low speed of 800r/min for 10 s. Then the film is obtained by rotating at a high speed of 3500r/min for 20 s. An alcohol cotton swab was used to wipe off a corner for use as the bottom electrode. And (3) placing the prepared wet film in a tube furnace, pre-annealing at 350 ℃ for 5min to crack organic matters, and then annealing at 550 ℃ for 20min to crystallize the film. The steps are repeated for at least six times and are all carried out in the atmospheric environment.
And 3, preparing the ZnO nanowire.
The ZnO nanowire is prepared and synthesized by a two-step hydrothermal method. The seed crystal layer is deposited on the BFO ferroelectric film by utilizing a radio frequency magnetron sputtering method, and the thickness of the seed crystal layer is about 100 nm. Sputtering conditions, background vacuum<4.5×10-4Pa, target spacing of 50mm, sputtering power of 80W, sputtering pressure of 2Pa, flow rate ratio of argon to oxygen of 40:2, substrate temperature of 500 ℃ and sputtering time of 5 min. And after the ZnO seed crystal layer is prepared, vertically growing a ZnO nanowire array along the c-axis direction of the ZnO seed crystal by using a hydrothermal method. The growth liquid is prepared by mixing 0.05M zinc nitrate hexahydrate [ Zn (NO)3)2·6H2O]And 0.0025M hexamethylene tetramethyAmine [ HMTA for short, (CH)2)6N4]Dissolving in 200ml deionized water, and adding 9ml ammonia water while stirring. Zinc nitrate hexahydrate provides zinc ions required by growth of the ZnO nanowire, hexamethylenetetramine serves as a weak base and a pH buffering agent at the same time, and appropriate ammonia water can inhibit homogeneous nucleation of a growth solution and reduce consumption, so that axial growth of the ZnO nanowire can be effectively promoted, and a long nanowire array can be grown.
Pouring the prepared growth liquid into a 200ml glass bottle, placing the substrate with the ZnO seed crystal layer in the solution with the surface facing downwards, sealing the glass bottle by using a Polytetrafluoroethylene (PTFE) sealing tape, placing the glass bottle in a forced air drying box at 90 ℃ for growth for 9 hours, taking out the glass bottle, cleaning the sample wafer by using absolute ethyl alcohol, and drying the sample wafer.
And 4, preparing the top electrode.
Transparent ITO is used as the top electrode to allow more incident light to pass through the film. The ITO electrode was deposited by magnetron sputtering, with an electrode area of 3mm by 3mm and a thickness of about 300 nm. Sputtering conditions of ITO electrodes, background vacuum<4.5×10-4Pa, Sputtering power source RF Sputtering, Sputtering power 80W, Sputtering pressure 2Pa, argon gas and oxygen gas flow rate ratio 50: 0, substrate temperature 350 ℃ and sputtering time 10 min.
And (3) testing the micro-morphology of the BFO film and the BFO/ZnO heterojunction, and characterizing the micro-morphology of the BFO film and the BFO/ZnO heterojunction by using a scanning electron microscope. Fig. 2 shows an SEM image of the BFO film on the FTO conductive glass, fig. 2(a) visually reflects that the BFO film has a uniform and dense surface and good flatness, and fig. 2(b) shows that the cross-sectional SEM image of the BFO film shows that the film thickness is 522nm and the boundary with the FTO conductive layer is clear, so we judge that the BFO film prepared by using the sol-gel spin coating method has good quality.
A ZnO seed crystal layer is grown on the prepared BFO surface by magnetron sputtering, and then a ZnO nanowire array with good orientation is vertically grown by a two-step hydrothermal method, as shown in figure 3. The surface SEM image of the BFO/ZnO heterojunction structure in FIG. 3(a) shows that the grown ZnO nanowire has a hexagonal crystal structure in the microstructure, the thickness of the nanorod is uniform, and the average diameter of the nanowire is about 190 nm. From the sectional view of fig. 3(b), it can be seen that the ZnO nanowires are in good contact with the BFO thin film, the boundaries are clear, most of the nanowires are vertically and closely arranged, and the growth lengths are relatively uniform, about 7 μm.
XRD analysis was performed on the BFO thin film and the BFO/ZnO heterojunction bilayer film, as shown in FIG. 4. Fig. 4(a) is an XRD spectrum of pure BFO on an FTO substrate, which shows that the prepared BFO thin film is of a polycrystalline perovskite structure, and no other impurity peak except for the FTO substrate peak is found after comparing the XRD diffraction peak with PDF, demonstrating that the BFO thin film has good crystallinity. An XRD (X-ray diffraction) spectrum of the ZnO nanowire grown on the BFO film is shown in fig. 4(b), a very strong diffraction peak of the ZnO nanowire is shown at a position with 2 theta being 34.43 degrees, and a (002) crystal face corresponding to ZnO is found by comparing with a PDF standard card, so that the ZnO nanowire grown by a hydrothermal method preferentially grows along the c-axis direction and has good crystallization performance.
Ferroelectric properties of the BFO film. The ferroelectric switching behavior of BFO thin films is mainly tested by Piezoelectric Force Microscopy (PFM) techniques. FIG. 5 is an out-of-plane PFM phase plot of a BFO film. As shown in FIG. 5, a +18V voltage is applied to a sample area with an outer frame of 3 μm × 3 μm for polarization, then an-18V electric field is applied to a sample area with an inner frame of 1 μm × 1 μm for polarization, and the color of the two polarized areas can be obviously changed by comparing, so that the BFO film has a certain polarization inversion phenomenon, and the BFO film is proved to have good piezoelectric property and 'electrographic' property. In addition, the color of a blue region polarized by the +18V voltage is close to that of a region not polarized by the applied electric field, which indicates that the BFO ferroelectric film has an upward spontaneous polarization phenomenon. The origin of this phenomenon is related to lattice mismatch, electron trapping or oxygen vacancies.
The phase curve and amplitude variation measured by PFM are typical characteristics of ferroelectric materials, as shown in fig. 6. Fig. 6(a) and (b) are graphs of phase and amplitude of the BFO film respectively as a function of an applied bias, and it can be seen from fig. 6(a) that the BFO film has a 180 ° phase change, indicating that a complete domain inversion phenomenon exists inside the BFO film, and the BFO film has a good local ferroelectricity. This is also demonstrated by the higher amplitude variation in the butterfly curve of fig. 6 (b).
BFO and ZnO nano-wire ultraviolet-visible light analysis. The optical transmittance and uv-visible light absorption of the BFO film and ZnO nanowires were measured by a uv-visible spectrophotometer, showing a wide visible light absorption range of the BFO film, as shown in fig. 7(a) and (b).
The absorption coefficient of the film and the corresponding wavelength can calculate the corresponding light wave energy, the optical band gap of the BFO film and the ZnO nanowire can be calculated by utilizing the Tauc formula (1),
(αhv)2＝A(hv-Eg) (1)
wherein alpha represents the absorption coefficient, h is the Planck constant, v represents the optical wave frequency, i.e. h v is the photon energy, and A is a constant. According to (alpha h v)2Plotting the relationship with photon energy and fitting calculation, as shown in fig. 7(c), we can obtain the effective optical band gaps of the BFO thin film and the ZnO nanowire to be 2.71eV and 3.25eV, respectively, which are basically consistent with the experimental results (2.73eV and 3.26eV) reported previously, and provide the band gap size support for analyzing the change of the photoelectric property of the BFO/ZnO heterostructure from the energy band structure.
In order to further explore the enhancement effect of the BFO/ZnO heterostructure on the ferroelectric property of the BFO film, two different types of device structures of ITO/BFO/FTO and ITO/ZnO NWs/BFO/FTO are prepared, J-V, J-T characteristic curves of the devices in a dark state and under illumination are respectively tested by utilizing a Keithley-2400 digital source table, and the photoelectric property and the carrier transport working mechanism of the devices in the two structures are researched. The BFO ultraviolet-visible light absorption performance is combined, the wavelength is 405nm, the power density is 200mW/cm in the test process2The obtained blue-violet light is used as an excitation light source to irradiate the BFO thin film and the BFO/ZnO heterojunction, and the obtained photoelectric characteristic curve is shown in figure 8. FIG. 8(a) is a current density versus voltage curve of a BFO film under dark conditions and under blue-violet light irradiation, and the photoelectric properties of the BFO film are clearly seen, as is its open-circuit voltage (V)OC) And short circuit current density (J)SC) Respectively at-0.28V and 0.3986mA/cm2. The BFO/ZnO heterojunction device prepared by introducing the ZnO nanowire also shows the same performance under the condition of blue-violet light irradiationGood photoelectric properties are obtained, and the photoelectric properties of the BFO/ZnO heterostructure are obviously much better than those of a pure BFO thin film, as shown in FIG. 8 (b). The short-circuit current of the BFO/ZnO heterostructure is greatly improved to 2.6374mA/cm2The short-circuit current of the BFO film is about 7 times, the open-circuit voltage is also improved in a small range, the voltage is increased from-0.28V to-0.42V, and the voltage is improved by 1.5 times.
The stability and repeatability of the photoelectric properties of the BFO film and the BFO/ZnO heterostructure are researched, current density and time response curves of two structures under zero bias are tested, as shown in fig. 8(c), it can be seen that after blue-violet light irradiation, the two structures have stable light current density generation, the size of the two structures is very close to the self short-circuit current density, after a light source is turned off, the light current density almost becomes zero, the photoelectric output performance hardly attenuates along with time under long-time test, the repeatability and stability of the two devices are illustrated, and meanwhile, the improvement of the photoelectric performance output of the BFO/ZnO heterostructure is displayed more visually by comparing two J-T curves. In addition, the BFO/ZnO heterojunction also accelerates the photoelectric response time of the device to some extent, as shown in fig. 8 (d). The BFO/ZnO heterojunction photoelectric response time is slightly reduced compared with the BFO thin film, the rising time is accelerated from 0.1416s to 0.1104s, and the falling time is increased from 0.1533s to 0.1270 s.
When the n-type ZnO nanowire and the BFO thin film are mutually contacted, a heterojunction is considered to be formed, the difference between the work functions of the BFO and the ZnO layer is 0.34eV, and the difference between the work functions can cause the generation of a built-in electric field E at an interfacebiThe direction is from ZnO to BFO. The BFO film has upward spontaneous polarization P, and generates depolarization electric field Edp. Under the illumination condition, the photon-generated carriers are separated and transported into an external circuit under the action of a BFO depolarization electric field, so that the BFO film shows photoelectric properties. EbiOrientation and E of BFO filmdpThe directions are the same, so that the separation effect of photogenerated carriers is accelerated, and the photoelectric performance of the device is improved.
In order to further improve the photoelectric performance of the BFO/ZnO heterojunction, a piezoelectric motor is utilized to apply compressive stress to a top electrode, and then a compressive acting force is applied to the BFO/ZnO heterojunction device at the top end of a c-axis of a ZnO nanowire to enable the nanowire to be strained, and the separation of carriers in a junction area of the BFO/ZnO heterojunction is promoted through piezoelectric potential generated when the nanowire is strained, so that the photoelectric performance of the heterojunction device is enhanced.
The photoelectric characteristic curve of the BFO/ZnO heterojunction device under the compressive stress in the dark state and under the illumination condition is shown in FIG. 9. FIGS. 9(a) and 9(b) are J-V curves of BFO/ZnO heterojunctions in dark and light conditions, respectively.
Under the dark condition, the dark current of the BFO/ZnO heterojunction device is continuously increased along with the increase of the compressive strain, and after illumination is applied, the photocurrent shows the same change trend as the dark current along with the increase of the compressive strain. The short-circuit current under illumination also increases along with the increase of the compressive strain, namely 0.7458mA/cm under the non-strain condition2Increased to 0.9030mA/cm with increasing strain to-1.3%2The increase is about 21%, but at the same time, the open-circuit voltage is slightly reduced, and the initial-0.31V is reduced to-0.30V after being subjected to-1.3% compressive strain, but the voltage is too weak relative to the increase of the short-circuit current, so that the compressive strain generated after the BFO/ZnO is subjected to an external compressive force has an effect of enhancing the photoelectric conversion efficiency of the whole heterojunction device, as shown in fig. 9 (c). As shown in fig. 9(d), the optical response curves of the BFO/ZnO heterojunction under different strains are measured under the state of no bias voltage, which shows the stability and repeatability of the photoelectric property of the structure under the stress state, and also proves that the BFO/ZnO heterojunction device can be applied to a novel piezoelectric-photoelectric energy conversion device and a sensor.
A schematic diagram of the band change of the BFO/ZnO heterojunction under the action of the strain is shown in figure 10. When the BFO film is in contact with the ZnO nanowire, electrons flow from the BFO film to one side of the ZnO nanowire, and thus a space charge region is formed at the interface. When compressive strain is applied to the BFO/ZnO heterojunction device on one side of the ZnO nanowire, negative voltage potential is generated in the + c axis direction of the ZnO nanowire, positive voltage potential is generated at the-c end of a BFO contact surface, piezoelectric charge generated by the piezoelectric potential cannot move, and cannot disappear on the premise that the strain exists consistently. The positive voltage potential at the interface of the BFO film and the ZnO nanowire can enable the energy band of the junction to move downwards to generate a recess, so that the Schottky barrier height of the interface of the BFO film and the ZnO nanowire is reduced. The current generated under reverse bias increases with increasing compressive strain. When 405nm of blue-violet light irradiates the BFO/ZnO heterojunction device, photo-generated electron hole pairs are separated under the action of an internal electric field, the holes move to the BFO side, and electrons move to the ZnO side to an electrode to form photocurrent. When the ZnO nanowire side is subjected to compressive strain, positive piezoelectric charges generated at the interface of the BFO thin film and the ZnO nanowire can increase the width of a depletion region at the BFO side. At this time, the built-in electric field is enhanced, and the separation of photon-generated carriers is promoted. Therefore, the photoelectric current of the BFO/ZnO heterojunction can also increase along with the increase of the compressive strain, and the photoelectric performance of the BFO/ZnO heterojunction is enhanced.
Claims (8)
1. A method for improving the photoelectric response of a BFO/ZnO heterojunction device is characterized by comprising the following steps: the BFO/ZnO heterojunction device comprises a bottom electrode, a BFO ferroelectric film, a ZnO seed crystal layer, a ZnO nanowire array and an upper electrode in sequence from bottom to top, wherein ZnO nanowires in the ZnO nanowire array grow along the c-axis direction; the dark current and the photocurrent of the BFO/ZnO heterojunction device are continuously increased along with the increase of the compressive strain; and the compressive strain adjustment is realized by applying compressive stress to the top direction of the c axis of the heterojunction ZnO nanowire by using a piezoelectric motor.
2. The method for improving the photoelectric response of the BFO/ZnO heterojunction device as claimed in claim 1, wherein the method comprises the following steps: the preparation method of the BFO/ZnO heterojunction device comprises the steps of preparing a BFO ferroelectric film on FTO conductive glass by adopting a sol-gel spin-coating method, preparing a ZnO seed crystal layer on the BFO ferroelectric film by utilizing magnetron sputtering, vertically and upwards growing ZnO nanowire arrays by using a hydrothermal method, and finally depositing an ITO transparent electrode by using magnetron sputtering.
3. The method for improving the photoelectric response of the BFO/ZnO heterojunction device as claimed in claim 1, wherein the method comprises the following steps: the ZnO nanowire array is prepared and synthesized by a two-step hydrothermal method, a ZnO seed crystal layer is deposited by a radio frequency magnetron sputtering method, and after the preparation of the ZnO seed crystal layer is finished, the ZnO nanowire array is vertically grown along the c-axis direction of the ZnO seed crystal by the hydrothermal method.
4. The method for improving the photoelectric response of the BFO/ZnO heterojunction device as claimed in claim 3, wherein the method comprises the following steps: the length of the ZnO nanowire in the ZnO nanowire array is 5-10 μm, and the diameter of the ZnO nanowire is 160-200 nm.
5. The method for improving the photoelectric response of the BFO/ZnO heterojunction device as claimed in claim 4, wherein the method comprises the following steps: after the light irradiation is applied, the short-circuit current increases with the increase of the compressive strain.
6. The method for improving the photoelectric response of the BFO/ZnO heterojunction device as claimed in claim 5, wherein: the seed crystal layer is deposited on the BFO ferroelectric film by utilizing a radio frequency magnetron sputtering method.
7. The method for improving the photoelectric response of the BFO/ZnO heterojunction device as claimed in claim 6, wherein: the BFO ferroelectric film is prepared by a spin coating method.
8. A piezoelectric-photoelectric energy conversion device using the method for improving the photoelectric response of the BFO/ZnO heterojunction device as claimed in any of claims 1 to 7.
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| CN106153223A (en) * | 2015-03-27 | 2016-11-23 | 北京纳米能源与系统研究所 | Strain gauge array and preparation method thereof and stress distribution sensor-based system and method for sensing |
| CN107256923A (en) * | 2016-08-29 | 2017-10-17 | 郑州工商学院 | A kind of preparation method with big photostrictive effectt device |
| CN109192855A (en) * | 2018-09-18 | 2019-01-11 | 陕西科技大学 | BEFMO/ZnO composite heterojunction with resistance switching effect and preparation method thereof |
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| Enhanced Photovoltaic Performance in Polycrystalline BiFeO3 Thin Film/ZnO Nanorod Heterojunctions;Fen Wu等;《The Journal of Physical Chemistry C》;20140630;摘要；正文第2页左栏实验部分；摘要附图 * |
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