Self-powered broadband photo-detecting device and method of fabricating the same

Abstract

The invention discloses a self-powered broadband photo-detecting device and a method of fabricating the same. The self-powered broadband photo-detecting device according to the invention includes a substrate, a plurality of nanorods and a plurality of nanoflake clusters. The plurality of nanorods are formed on an upper surface of the substrate. The plurality of nanorods are formed of an oxide of a metal. Each nanoflake cluster is formed on a respective top of one of the plurality of nanorods. The plurality of nanoflake clusters are formed of a chalcogenide of the metal.

Description

Self-powered broadband optical detection element and its manufacturing method This invention relates to a self-powered broadband optical detection element and its manufacturing method, and to a self-powered broadband optical detection element and its manufacturing method that integrates one-dimensional and two-dimensional nanostructures, utilizes metal chalcogenides, and possesses excellent properties. Existing research has confirmed that the performance of photodetectors (PDs) can be significantly improved by utilizing the light-induced pyroelectric effect (also known as the pyro-phototronic effect, PPE). In this effect, the illumination-induced temperature gradient generates a thermal potential difference on the photodetector material. When this potential difference combines with the built-in potential difference of the heterostructure, the charge transport of the entire device can be modulated. Pyroelectric semiconductors can induce pyroelectric polarization by changing the temperature gradient of the material over time. Many studies have utilized the photosensitive element-dependent polymorphism (PPE) effect in photodetectors. Zhaona Wang et al. pioneered a ZnO / perovskite heterojunction photodetector. Photoinduced PPE in the ZnO nanowires significantly enhances the photodetector's performance. Under ultraviolet light irradiation, the PPE effect significantly improves the detection rate and responsivity by 322%. Similarly, Zhaona Wang et al.'s research on p-Si / n-ZnO heterojunction photodetectors also showed a significant improvement in performance due to the photoinduced PPE effect, with a 599% increase in responsivity under ultraviolet light irradiation. Jihong Liu et al. explored a Cu(In, Ga)Se... A multilayer heterojunction photodetector, due to a synergistic mechanism, significantly enhanced the responsivity by 505.5% and the detection rate by 519.4% under 808 nm wavelength illumination. Jihong Liu et al. in Cu(In, Ga)Se... Studies of two-layer heterojunctions have revealed that, under illumination in the 405-1064 nm wavelength range, they exhibit highly sensitive and elastic sensing capabilities that can be tuned by combining piezoelectric and pyroelectric effects. Xuemei Zheng et al. investigated gold-plated modified PbI₂... 2 / ZnO heterojunctions, although limited to UV detection, improve photodetector performance due to the incorporation of the PPE effect. While some photodetectors based on the single-layer PPE effect have high efficiency, they are limited by insufficient spectral detection range, inadequate efficiency, and high cost, among other factors. Furthermore, low-dimensional materials, especially one-dimensional nanopillars and two-dimensional nanosheets, play a crucial role in achieving higher performance broadband photodetectors due to their high specific surface area and unique, superior properties. Metal sulfides, with their unique properties and diverse applications, including high electron mobility, good chemical stability, and suitability for sensors, energy storage devices, supercapacitors, and lithium-ion batteries, are attracting increasing attention from researchers. However, no technology has yet been proposed to integrate these nanostructures and materials to significantly improve the photoelectric performance of broadband photodetectors. Therefore, one of the technical problems to be solved by the present invention is to provide a self-powered broadband optical detection element that integrates one-dimensional and two-dimensional nanostructures, utilizes metal chalcogenides and has excellent photoelectric properties, and a method for manufacturing the same. A self-powered broadband optical detection element according to a preferred embodiment of the present invention comprises a substrate, a plurality of nanopillars, and a plurality of nanosheet clusters. The substrate has an upper surface. The plurality of nanopillars are formed on the upper surface of the substrate. The plurality of nanopillars are formed of a metal oxide compound. The metal may be tin, germanium, lead, arsenic, germanium, phosphorus, antimony, boron, aluminum, gallium, indium, titanium, sodium, etc. Each nanosheet cluster is formed at the tip of one of the plurality of nanopillars. The plurality of nanosheet clusters are formed of a chalcogenide compound of the metal. In one specific embodiment, the chalcogen element in the chalcogen compound may be sulfur, selenium, tellurium, polonium, protium, etc. In one specific embodiment, the substrate may be formed of materials such as glass, metal, ceramic, polymer, and semiconductor. In one specific embodiment, under illumination with light of wavelength 850nm, the responsivity of the self-powered broadband optical detection element according to a preferred embodiment of the present invention is equal to or greater than 2.6mA / W. According to a preferred embodiment of the present invention, a method for manufacturing a self-powered broadband optical detection element firstly involves preparing a substrate. The substrate has an upper surface. Next, according to a preferred embodiment of the present invention, a plurality of nanopillars are formed on the upper surface of the substrate using a first hydrothermal method. The plurality of nanopillars are formed from an oxide compound of a metal. The metal may be tin, germanium, lead, arsenic, germanium, phosphorus, antimony, boron, aluminum, gallium, indium, titanium, sodium, etc. Finally, according to a preferred embodiment of the present invention, a plurality of nanosheet clusters are formed using a second hydrothermal method. Each nanosheet cluster is formed on the top of one of the plurality of nanopillars. The plurality of nanosheet clusters are formed from a chalcogenide compound of the metal. Unlike prior art, the self-powered broadband optical detection element of the present invention integrates one-dimensional and two-dimensional nanostructures and utilizes metal chalcogenide compounds, and exhibits excellent performance. The self-powered broadband optical detection element of the present invention is conducive to commercialization. The advantages and spirit of this invention can be further understood from the following detailed description of the invention and the accompanying drawings. Please refer to Figure 1, which schematically illustrates a self-powered broadband optical detection element 1 according to a preferred embodiment of the present invention in an external view. As shown in FIG1, a self-powered broadband optical detection element 1 according to a preferred embodiment of the present invention includes a substrate 10, a plurality of nanopillars 12 and a plurality of nanosheet clusters 14. In one embodiment, the substrate 10 has an upper surface 102. In one embodiment, the substrate 10 may be formed of materials such as glass, metal, ceramic, polymer, and semiconductor. Taking polymer materials as an example, the substrate 10 may be formed of polyetheretherketone (PEEK). A plurality of nanopillars 12 are formed on the upper surface 102 of the substrate 10. The plurality of nanopillars 12 are formed of a metal oxide compound. In particular, the metal may be tin, germanium, lead, arsenic, germanium, phosphorus, antimony, boron, aluminum, gallium, indium, titanium, sodium, etc. Each nanosheet cluster 14 is formed on the tip of one of the plurality of nanopillars 12. In particular, the plurality of nanosheet clusters 14 are formed from a chalcogenide compound of the metal. In one specific embodiment, the chalcogen element in the chalcogen compound may be sulfur, selenium, tellurium, polonium, protium, etc. In one specific embodiment, under illumination with light of wavelength 850nm, the responsivity of the self-powered broadband optical detection element 1 according to a preferred embodiment of the present invention is equal to or higher than 2.6mA / W. Please refer to Figures 2 to 3 and Figure 1, which are cross-sectional views illustrating a method for manufacturing the self-powered broadband optical detection element 1 shown in Figure 1 according to a preferred embodiment of the present invention. As shown in Figure 2, the method for manufacturing a self-powered broadband optical detection element 1 according to a preferred embodiment of the present invention involves preparing a substrate 10. The substrate 10 has an upper surface 102. In one embodiment, the substrate 10 has an upper surface 102. In one embodiment, the substrate 10 can be formed of materials such as glass, metal, ceramic, polymer, and semiconductor. Taking polymer materials as an example, the substrate 10 can be formed using polyetheretherketone (PEEK). As shown in Figure 3, the method according to a preferred embodiment of the present invention then involves forming a plurality of nanopillars 12 on the upper surface 102 of the substrate 10 using a first hydrothermal process. The plurality of nanopillars 12 are formed from a metal oxide compound. Specifically, the metal can be tin, germanium, lead, arsenic, germanium, phosphorus, antimony, boron, aluminum, gallium, indium, titanium, sodium, etc. Finally, according to a preferred embodiment of the present invention, a plurality of nanosheet clusters 14 are formed by a second hydrothermal process, thereby completing the self-powered broadband optical detection element 1 according to the present invention as shown in FIG. 1. Each nanosheet cluster 14 is formed on the top of one of the plurality of nanopillars 12. In particular, the plurality of nanosheet clusters 14 are formed of a chalcogenide compound of the metal. In one specific embodiment, the chalcogen element in the chalcogen compound may be sulfur, selenium, tellurium, polonium, protium, etc. In one specific embodiment, under illumination with light of wavelength 850nm, the responsivity of the self-powered broadband optical detection element 1 according to a preferred embodiment of the present invention is equal to or greater than 2.6 mA / W. In one example, the method according to the invention involves forming a plurality of SnO roots on the upper surface of a p-type silicon substrate by a first hydrothermal process. 2-nanometer column. This example first involves placing 1.107 g of SnCl₂ into a column. 4⋅5H 2O and 0.9g NaOH were added to deionized water (40mL) and stirred magnetically for 30 minutes until both chemicals were completely dissolved. Next, the p-type silicon substrate and the above solution were placed in a 100mL stainless steel autoclave with a Teflon liner, sealed, heated and cooled in a heat treatment furnace, and then dried at 100°C in the atmosphere. Finally, the structure obtained from the first hydrothermal process of this example was dried at 50°C in the atmosphere for 13 hours. Then, SnS was synthesized on the above structure using a second hydrothermal process. 2-nanometer clusters. This example continues with 0.3793g of thiourea (CH) 4N 2S) and 1.2126g of tin chloride pentahydrate (SnCl) 4⋅5H 2O) The mixture was stirred in 40 mL of deionized water for one hour to ensure uniform dispersion. Then, the resulting mixture was transferred to a Teflon container, sealed in a stainless steel autoclave, and heat-treated at 200°C for 24 hours. After the system cooled, the final product was left at room temperature for 12 hours and washed multiple times with water and ethanol. Subsequently, the mixture was dripped (range 0–1000 μL) onto Si / SnO using a micropipette. It was placed on a 2-nanometer column and then on a hot plate at 60°C for 12 hours. Then, on SnS... 2 / SnO A layer of platinum was sputtered onto the top electrode, while Ag was deposited on the lower surface of the p-type silicon substrate as the bottom electrode to test the photoelectric detection characteristics. Please refer to Figures 4 and 5. These figures illustrate images of different structures captured using field emission scanning electron microscopy (FESEM) in the above examples to analyze surface morphology and microstructure. Figure 4 shows the SnO in this example. FESEM image of a 2 nm column. Figure 5 shows the SnO in this example. 2 / SnS 2. FESEM images of heterostructures and single SnO 2 / SnS 2. Magnified high-resolution FESEM image of heterostructured nanosheet clusters. The FESEM image shown in Figure 4 displays SnO. The 2-nanometer columnar array is vertically aligned, resembling a grass-like structure growing in all directions. SnO The average height of the 2-nanometer column is approximately 3.12 μm. The FESEM image shown in Figure 5 reveals SnO. SnS on 2 nanometer pillars The morphology of the 2-nanometer clusters appears relatively dispersed. In Figure 5, the FESEM image shows SnS... 2-nanometer clusters form a three-dimensional structure based on two-dimensional nanosheets, with an average size of 3.50 ± 0.50 μm. High-magnification FESEM images reveal a consistent flower-like morphology containing nanosheets, each approximately 110 nm thick. This striking morphology is due to SnS... 2 with SnO This is due to the extremely small lattice dislocations between the two. This morphology is beneficial for carrier transport to the photoactive surface. Please refer to Figure 6, which shows the formation of SnO on a p-type silicon substrate in the above example. 2 and SnO 2 / SnS Figure 6 shows the X-ray diffraction (XRD) pattern analysis results. The crystal structure and phase composition of the synthesized composite in the above example were determined using the XRD pattern. The XRD pattern in Figure 6 confirms the formation of SnS... Before 2, all diffraction peaks were related to SnO. The diffraction peak is consistent with that of 2(JCPDS 41-1445). It exhibits a peak at 26.57. o The main diffraction peaks indicate that SnO The 2-nanometer pillars primarily grew along the (110) direction. In SnO... After the 2-nanometer pillar was formed, the observed diffraction peak was at a 2θ value of 15.26. o 28.68 o 32.59 o 42.24 o 50.41 o and 52.83 o With Hexagonal SnS The index database of 2 (JCPDS 23-0677) is precisely aligned to the (001), (100), (011), (012), (110) and (111) crystal planes, respectively. The above example of p-Si / SnO 2 / SnS 2. Current-voltage (IV) and current-time (It) characteristics of the heterostructure were measured under darkness and illumination by light sources of different wavelengths. As a control, SnO was formed on a p-type silicon substrate. 2 nanoparticle column (p-Si / SnO) 2) Comparative example and SnS formation on p-type silicon substrate 2 nanometer clusters (p-Si / SnS) 2) The control example also underwent measurements of current-voltage (IV) and current-time (It) characteristics. Please refer to Figures 7, 8, and 9. Figure 7 shows the p-Si / SnO of the above example. 2 / SnS 2. Current and voltage (IV) results of the heterostructure under illumination by light sources of different wavelengths (365~850nm), with a power density of 2 mW / cm². 2 Figures 8 and 9 show p-Si / SnO, respectively. 2. Structure and p-Si / SnS Figure 2 shows the current and voltage (IV) results of the structure under illumination by light sources of different wavelengths (365~850nm), with a power density of 2mW / cm². 2 The results shown in Figures 7, 8, and 9 confirm that the above-mentioned p-Si / SnO 2 / SnS 2. The heterostructure photodetector exhibits self-powered photovoltaic (PV) behavior, with an open-circuit voltage (Vo) at wavelengths of 365, 456, 532, 632, and 850 nm. OC The short-circuit currents (I) are -0.19, -0.14, -0.13, -0.09, and -0.05V, respectively. SC The λ values ​​were 0.022, 0.019, 0.018, 0.013, and 0.012 μA, respectively. Under illumination at wavelengths of 365, 456, 532, 632, and 850 nm, the p-Si / SnO... 2 / SnS 2 heterostructure I SC Approximately p-Si / SnO 4, 2.8, 2.8, 2 and 1.9 times the strength of 2 nanometer pillars, and p-Si / SnS The observed self-powered photovoltaic behavior can be attributed to the built-in electric field facilitating the efficient separation of electron-hole pairs between different materials, which in turn disrupts thermal equilibrium, leading to photovoltage. Therefore, these findings highlight the potential for vertical p-Si / SnO... 2 / SnS 2. The effectiveness of heterogeneous structure optical detection elements in self-powered optical detection applications. Please refer to Figures 10 to 16. Figures 10 to 14 show the p-Si / SnO of the above examples. 2 / SnS Figure 2 shows the current versus time (It) results of the heterostructure under illumination at different wavelengths (365, 456, 532, 632, and 850 nm) and different lighting intensities. The inset in Figure 10 shows an enlarged It curve. Figure 15 shows the p-Si / SnO series. 2. Structures at different wavelengths (365, 456, 532, 632, and 850 nm) with an illumination intensity of 2 mW / cm² 2The current versus time (It) results under illumination by the light source are shown in Figure 16. 2. Structures at different wavelengths (365, 456, 532, 632, and 850 nm) with an illumination intensity of 2 mW / cm² 2 The results of current versus time (It) under illumination by the light source are shown in Figures 10 to 16. The results show that there are significantly different four-stage photocurrent behaviors under different wavelength spectra (365, 456, 532, 632 and 850 nm) and different illumination intensities, demonstrating the wide photoresponse range of the PPE-induced emission detection element. Considering the significant difference in the shape of the It curve, this invention can reasonably infer that the sharp peak is induced by the PPE-PV coupling effect, which in turn is caused by the temperature rise induced by instantaneous light within the photodetector element. (This is in contrast to p-Si / SnO.) 2 and p-Si / SnS Compared to 2, p-Si / SnO 2 / SnS The heterostructure exhibits excellent PPE-PV coupling under a broad spectral illumination range of 365 to 850 nm. For light wavelengths below 850 nm, the photocurrent (Ig) is significantly higher. s ) and pyroelectric current (I ts ) and photocurrent (I s ) and transient current (I t The sum of all these increases with increasing wavelength. Furthermore, although light with a wavelength of 850 nanometers exceeds the SnS... 2 and SnO The bandgap absorption range is 2, but as shown in Figure 14, the photodetector exhibits response behavior in both the on and off phases. The decrease at 850 nm compared to other wavelengths can be attributed to non-photogenerating carriers. In the inset of Figure 10, the corresponding maximum output photocurrent is expressed as I... t I s 、I' t and I' s In the initial stage, the sharp peak (I) induced by the PPE-PV coupling effect under illumination. tThis corresponds to the instantaneous temperature rise within the photodetector element. In the following stage, the pyroelectric potential gradually decreases as the temperature change diminishes, while maintaining continuous illumination to form a stable output current (I0). s In the third stage, after the lighting is turned off, the output current (I') will be observed. t The rapid drop in pyroelectric potential is due to the reverse pyroelectric potential caused by the instantaneous temperature decrease. In the fourth stage, when the temperature stabilizes at room temperature, the pyroelectric potential gradually weakens due to leakage and screening, causing the output current to return to a stable high point, known as dark current, denoted as I. s . The above example of p-Si / SnO 2 / SnS 2. Illumination intensity current and absolute output current (IL) of heterostructured photodetector under illumination of 365, 456, 532, 632 and 850 nanometer wavelengths. t , I s ) and peak-to-peak instantaneous current (I tt ' = I t - I' t A comprehensive comparative analysis, summary, and explanation of the output photocurrent I. t (Absolute transient current), I s (Absolutely stable current) and I tt The relative transient current is positively correlated with illumination intensity. Using both absolute and relative currents as evaluation parameters, the photosensing performance of photodetectors utilizing PPE can be effectively assessed. Higher illumination intensity accelerates temperature changes, generating a more pronounced pyroelectric current. The observed four-stage decrease in photocurrent at decreasing light intensity can be attributed to the limited generation of photogenerating carriers, with only a few traps occupied, leading to a corresponding decrease in the trap-assisted recombination rate. As light intensity increases, the number of photogenerating carriers increases significantly, resulting in an increased trap-assisted recombination rate and exhibiting a transient photocurrent peak. These results demonstrate that the Si / SnO according to the present invention… 2 / SnS 2. The occurrence and occurrence of instantaneous photocurrent peaks in heterostructured photodetectors (SnS) 2 / SnO 2 / Si interface and SnS 2 / SnO 2. Defects at grain boundaries are involved in the carrier recombination process. This shows that higher illumination power densities are more conducive to achieving PPE-PV coupling effects in the device. According to the Si / SnO of the present invention 2 / SnS 2. Heterogeneous structure photodetectors at wavelengths of 365, 456, 532, 632, and 850 nm with an illumination intensity of 2 mW / cm² 2 Irradiation by a light source and at zero bias with bare Si / SnS Compared to 2, it has enhanced peak-to-peak instantaneous current (I0). tt The percentages were 9214%, 33291%, 121972%, 109091%, and 7496%, respectively, while the pyroelectric current (I) ts The responsivity can be increased to 16733%, 97643%, 219400%, 291333%, and 26777%, respectively. When the pyroelectric photonic effect is added to the heterostructure, the responsivity of the photodetector is also significantly enhanced, reaching 3.65, 2.40, 9.28, 10.44, and 2.71 mA / W, respectively, which correspond to increases of 1952%, 2600%, 28114%, 18545%, and 491%. This invention provides an effective method to enhance the performance of a self-powered broadband photodetector by integrating the pyroelectric photonic effect into a hybrid-dimensional photodetector. These results show that the self-powered broadband optical detection element according to the present invention, affected by the PV-PPE coupling effect, has a faster response time than the response time driven solely by the PV effect. Furthermore, the performance of the self-powered broadband optical detection element according to the present invention significantly surpasses that of prior art PPE-based optical detection elements. Through the detailed description of the preferred embodiments above, it will be clear that the self-powered broadband optical detection element according to the present invention integrates one-dimensional and two-dimensional nanostructures and utilizes metal chalcogenide compounds, and possesses excellent performance. The self-powered broadband optical detection element according to the present invention is conducive to commercialization. The detailed description of the preferred embodiments above is intended to more clearly illustrate the features and spirit of the invention, and is not intended to limit the scope of the invention to the preferred embodiments disclosed above. Rather, the aim is to cover various modifications and equivalent arrangements within the scope of the patent claims made by this invention. Therefore, the scope of the patent claims made by this invention should be interpreted in the broadest possible sense based on the foregoing description, so as to cover all possible modifications and equivalent arrangements. 1: Self-powered broadband optical detection element; 10: Substrate; 102: Top surface; 12: Nano pillars; 14: Nanosheet clusters Figure 1 is an external view of a self-powered broadband optical detection element according to a preferred embodiment of the present invention. Figures 2 and 3 are external views of the structures obtained at various process stages of the method for manufacturing the self-powered broadband optical detection element shown in Figure 1 according to a preferred embodiment of the present invention. Figure 4 is an example of SnO according to the present invention. 2-nanometer column field emission scanning electron microscope (FESEM) image. Figure 5 shows an example of SnO from this invention. 2 / SnS 2. FESEM images of heterostructures. Figure 6 shows an example of the present invention: SnO formed on a p-type silicon substrate. 2 and SnO 2 / SnS Figure 7 shows the X-ray diffraction (XRD) pattern of p-Si / SnO as an example of this invention. 2 / SnS 2. Heterogeneous structures at different wavelengths with a power density of 2 mW / cm² 2 The current and voltage (IV) results under illumination by the light source are shown in Figure 8. Figure 8 shows the p-Si / SnO control example. 2. Structures at different wavelengths with a power density of 2 mW / cm² 2 The current and voltage (IV) results under illumination by the light source are shown in Figure 9. Figure 9 shows the p-Si / SnS control example. 2. Structures at different wavelengths with a power density of 2 mW / cm² 2 The current and voltage (IV) results under illumination by the light source are shown in Figure 10. Figure 10 shows an example of p-Si / SnO from this invention. 2 / SnS Figure 2 shows the current versus time (It) results of the heterostructure under illumination with light sources of different intensities at a wavelength of 365 nm. Figure 11 is an example of p-Si / SnO of the present invention. 2 / SnS Figure 12 shows the current versus time (It) results of the heterostructure under illumination with light sources of different intensities at a wavelength of 456 nm. 2 / SnS Figure 2 shows the current versus time (It) results of the heterostructure under illumination with light sources of different intensities at a wavelength of 532 nm. Figure 13 shows an example of p-Si / SnO from this invention. 2 / SnS Figure 2 shows the current versus time (It) results of the heterostructure under illumination with light sources of different intensities at a wavelength of 632 nm. Figure 14 shows an example of p-Si / SnO from this invention. 2 / SnS 2. Current versus time (It) results of the heterostructure under illumination with light sources of different intensities at a wavelength of 850 nm. Figure 15 shows the p-Si / SnO control example. 2. Structures at different wavelengths with an illumination intensity of 2 mW / cm 2 The results of current versus time (It) under illumination by the light source are shown in Figure 16. Figure 16 shows the p-Si / SnS control example. 2. Structures at different wavelengths with an illumination intensity of 2 mW / cm 2 The result of current versus time (It) under illumination by a light source. 1: Self-powered broadband optical detection element 10: Substrate 102: Upper surface 12: Nano Columns 14: Nano Clusters

Claims

1. A self-powered broadband optical detection element includes: a substrate having an upper surface; a plurality of nanopillars formed on the upper surface of the substrate, the plurality of nanopillars being formed of a metal oxide compound, wherein the metal is selected from the group consisting of tin, germanium, lead, arsenic, germanium, phosphorus, antimony, boron, aluminum, gallium, indium, titanium, and sodium; and a plurality of nanosheet clusters, each nanosheet cluster being formed on the top of one of the nanopillars, the plurality of nanosheet clusters being formed of a chalcogenide compound of the metal. The self-powered broadband optical detection element as described in claim 1, wherein one of the chalcogen elements in the chalcogen compound is selected from the group consisting of sulfur, selenium, tellurium, polonium and piezium. The self-powered broadband optical detection element as described in claim 2, wherein the substrate is formed of one of the group consisting of glass, metal, ceramic, polymer and semiconductor. The self-powered broadband optical detection element as described in claim 3, wherein under illumination by light of a wavelength of 850 nm, the responsivity of the self-powered broadband optical detection element is equal to or greater than 2.6 mA / W. A method for manufacturing a self-powered broadband optical detection element includes the following steps: preparing a substrate having an upper surface; forming a plurality of nanopillars on the upper surface of the substrate by a first hydrothermal process, wherein the plurality of nanopillars are formed of a metal oxide compound, the metal being selected from the group consisting of tin, germanium, lead, arsenic, germanium, phosphorus, antimony, boron, aluminum, gallium, indium, titanium, and sodium; and forming a plurality of nanosheet clusters by a second hydrothermal process, each nanosheet cluster being formed on the top of one of the nanopillars, wherein the plurality of nanosheet clusters are formed of a chalcogenide compound of the metal. The method as described in claim 5, wherein one of the chalcogen elements in the chalcogen compound is selected from the group consisting of sulfur, selenium, tellurium, polonium and pirimicarbium. The method described in claim 6, wherein the substrate is formed from one of the group consisting of glass, metal, ceramic, polymer and semiconductor. The method described in claim 7, wherein under illumination by light of a wavelength of 850 nm, the responsivity of one of the self-powered broadband optical detection elements is equal to or greater than 2.6 mA / W.