A memristor based on two-dimensional layered copper-based chalcogenide and its preparation method

Abstract

The present invention discloses a method for preparing a memristor based on a two-dimensional layered copper-based chalcogenide compound, comprising the following steps: Step 1, depositing a conductive film on a substrate as a bottom electrode using a sputtering or evaporation process; Step 2, preparing a two-dimensional layered copper-based chalcogenide material and transferring it to the bottom electrode using a transfer method to serve as a memristor functional layer; Step 3, depositing a Cu conductive layer on the memristor functional layer using a sputtering or evaporation process; Step 4, evaporating a metal layer on the Cu conductive layer as a top electrode, ultimately obtaining a memristor based on the two-dimensional layered copper-based chalcogenide compound. The memristor prepared by the present invention utilizes the Cu vacancies inherent in the copper-based chalcogenide compound as Cu ion migration channels, has a low migration barrier, does not require an additional heterogeneous layer on the surface, and thus has a low switching voltage (<1V).

Description

Technical Field

[0001] The present invention relates to a memristor based on a two-dimensional layered copper-based chalcogenide compound and a preparation method thereof, which is used in the field of memristor preparation. Background Art

[0002] Memristors are core components of integrated computing systems and artificial neural networks, and have advantages such as large-scale preparation, multi-state conversion, fast switching, and CMOS process compatibility. Currently, the main memristor active materials used to prepare memristors are Ta2O 5-x , HfO 2-x , TiO 2-x Oxides such as metal oxides are used to form conductive filaments by the migration of oxygen vacancies under the action of an electric field, thereby switching the memristor device between high and low resistance states. However, due to the high barrier to oxygen vacancy migration, the device switching voltage is large, which is not conducive to the integration of memristor devices. Literature reports that by introducing two-dimensional MoS2 between the metal electrode and the oxide, the switching voltage of the memristor device is reduced from -3.5V to -0.8V. Currently, among memristor devices realized using two-dimensional materials, a variety of low switching voltage (<1V) memristor devices have been realized. For example, by forming an extremely thin oxide layer on the surface of two-dimensional materials such as SnSe and MoS2, the device has an ultra-low switching voltage. However, the device surface formed by this method requires an additional heterogeneous layer, and the preparation method is complex and difficult. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a memristor based on a two-dimensional layered copper-based chalcogenide and a preparation method thereof. The two-dimensional layered copper-based chalcogenide is used as the active material of the memristor, and the Cu vacancies inherent in the copper-based chalcogenide are used as the Cu ion migration channel. The migration barrier is low, and no additional heterogeneous layer is required on the surface. The device has a low switching voltage (<1V).

[0004] A technical solution to achieve the above object is: a method for preparing a memristor based on a two-dimensional layered copper-based chalcogenide compound, comprising the following steps:

[0005] Step 1: depositing a conductive film as a bottom electrode on a substrate by sputtering or evaporation process;

[0006] Step 2: Prepare a two-dimensional layered copper-based chalcogenide material and transfer it to the bottom electrode by a transfer method to serve as a memristive functional layer;

[0007] Step 3, depositing a Cu conductive layer on the memristor functional layer by sputtering or evaporation process;

[0008] Step 4: evaporate a metal layer on the Cu conductive layer as a top electrode, and finally obtain a memristor based on a two-dimensional layered copper-based chalcogenide compound.

[0009] Furthermore, the substrate is one of Si, sapphire, glass, PET, PC, and PP.

[0010] Furthermore, the bottom electrode is FTO, AZO, Au, Pt, Pd, Ti, Ag, Ir or graphene, and the thickness of the bottom electrode is 10-500 nm.

[0011] Furthermore, the compound composition of the two-dimensional layered copper-based chalcogenide is BiCuOX, wherein X is one or both of S and Se.

[0012] Furthermore, the two-dimensional layered copper-based chalcogenide compound is prepared from a copper-based chalcogenide compound single crystal by a mechanical exfoliation method, and the thickness of the two-dimensional layered copper-based chalcogenide compound is 2-500 nm.

[0013] Furthermore, the two-dimensional layered copper-based chalcogenide is transferred to the bottom electrode using a dry or wet transfer method.

[0014] The memristor prepared by the above method includes, from bottom to top, a substrate, a bottom electrode, a two-dimensional layered copper-based chalcogenide, a Cu conductive layer and a top electrode.

[0015] Furthermore, the thickness of the Cu conductive layer is 2-20 nm, and the top electrode is an inert electrode, which is one of Au, Pt, Ir, Pd or graphene.

[0016] The advantages of the present invention are:

[0017] 1. The present invention utilizes two-dimensional BiCuOX (X is one or both of S and Se) as a memristive functional material. Compared with other two-dimensional materials, it has Cu vacancies that can be used to form a conductive channel, ultimately achieving a low switching voltage.

[0018] 2. BiCuOX (Bi2O2) 2+ The layer is an insulating layer, (Cu2X2) 2- It is a conductive layer, and the conductive path is along (Cu2X2) 2- layer, forming conductive filaments with high directionality, not easy to bifurcate, and high repeatability of switching voltage of memristive device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of a memristor based on a two-dimensional layered copper-based chalcogenide compound of the present invention;

[0020] Figure 2 The figure is a voltage-current curve of a two-dimensional layered BiCuOSe memristor device prepared by the method of the present invention. DETAILED DESCRIPTION

[0021] In order to better understand the technical solution of the present invention, the following is a detailed description through specific embodiments:

[0022] The present invention provides a method for preparing a memristor based on a two-dimensional layered copper-based chalcogenide compound, comprising the following steps:

[0023] Step 1: Deposit a conductive film as a bottom electrode on a substrate using a sputtering or evaporation process. The substrate can be an inorganic or organic substrate such as Si, sapphire, glass, PET, PC, or PP. The bottom electrode can be made of a material such as FTO, AZO, Au, Pt, Pd, Ti, Ag, Ir, or graphene. The thickness of the bottom electrode is 10-500 nm, preferably 15-40 nm.

[0024] Step 2: Prepare a two-dimensional layered copper-based chalcogenide material and transfer it to the bottom electrode via a transfer method to serve as the memristive functional layer. The two-dimensional layered copper-based chalcogenide has a compound composition of BiCuOX, where X is one or both of S and Se. The two-dimensional layered copper-based chalcogenide is prepared from a copper-based chalcogenide single crystal using a mechanical exfoliation method. The thickness of the two-dimensional layered copper-based chalcogenide is 2-500 nm, preferably 5-50 nm. The two-dimensional layered copper-based chalcogenide is transferred to the bottom electrode using a dry or wet transfer method, where dry methods include PDMS and PVA.

[0025] Step 3: depositing a Cu conductive layer on the memristor functional layer by sputtering or evaporation process.

[0026] Step 4: evaporate a metal layer on the Cu conductive layer as a top electrode, and finally obtain a memristor based on a two-dimensional layered copper-based chalcogenide compound.

[0027] See also Figure 1 The memristor prepared by the above method includes, from bottom to top, a substrate 1, a bottom electrode 2, a two-dimensional layered copper-based chalcogenide 3, a Cu conductive layer 4 and a top electrode 5.

[0028] The thickness of the Cu conductive layer is 2-20 nm, preferably 5-10 nm. The top electrode is an inert electrode, which is made of one of Au, Pt, Ir, Pd or graphene.

[0029] Example:

[0030] A 30 nm Au bottom electrode was prepared on a single-side oxidized Si substrate using photolithography and electron beam evaporation technology. The electron beam evaporation chamber pressure was 10 -5Pa, with an evaporation rate of 0.5 angstroms / second. The peeled BiCuOSe nanosheets were transferred to the bottom electrode using PDMS, and a 10nm thick Cu conductive layer was deposited on the BiCuOSe using electron beam coating technology. Finally, a 50nm thick Au top electrode was evaporated on the Cu conductive layer, thus completing the preparation of a two-dimensional layered copper-based chalcogenide memristor device (device structure see Figure 1 ). The current-voltage curve of the device is as follows Figure 2 As shown, the switching voltage of the display device is less than 1V.

[0031] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present invention and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for preparing a memristor based on a two-dimensional layered copper-based chalcogenide compound, characterized in that: The steps include: Step 1: depositing a conductive film as a bottom electrode on a substrate by sputtering or evaporation process; Step 2: Prepare a two-dimensional layered copper-based chalcogenide material and transfer it to the bottom electrode by a transfer method to serve as a memristive functional layer; Step 3, depositing a Cu conductive layer on the memristor functional layer by sputtering or evaporation process; Step 4: Deposit a metal layer on the Cu conductive layer as the top electrode, and finally obtain a memristor based on a two-dimensional layered copper-based chalcogenide. The compound composition of the two-dimensional layered copper-based chalcogenide is BiCuOX, where X is one or both of S and Se.

2. The method for preparing a memristor based on a two-dimensional layered copper-based chalcogenide compound according to claim 1, characterized in that: The substrate is one of Si, sapphire, glass, PET, PC, and PP.

3. The method for preparing a memristor based on a two-dimensional layered copper-based chalcogenide compound according to claim 1, characterized in that: The bottom electrode is FTO, AZO, Au, Pt, Pd, Ti, Ag, Ir or graphene, and the thickness of the bottom electrode is 10-500 nm.

4. The method for preparing a memristor based on a two-dimensional layered copper-based chalcogenide compound according to claim 1, characterized in that: The two-dimensional layered copper-based chalcogenide compound is prepared from a copper-based chalcogenide compound single crystal by using a mechanical exfoliation method. The thickness of the two-dimensional layered copper-based chalcogenide compound is 2-500 nm.

5. The method for preparing a memristor based on a two-dimensional layered copper-based chalcogenide compound according to claim 1, characterized in that: The two-dimensional layered copper-based chalcogenide is transferred to the bottom electrode using a dry or wet transfer method.

6. A memristor manufactured by the method according to any one of claims 1 to 5, characterized in that: From bottom to top, it includes a substrate, a bottom electrode, a two-dimensional layered copper-based chalcogenide, a Cu conductive layer and a top electrode.

7. The memristor according to claim 6, wherein: The thickness of the Cu conductive layer is 2-20 nm, and the top electrode is an inert electrode, which is one of Au, Pt, Ir, Pd or graphene.

Images