Light-emitting device and preparation method thereof

Abstract

The invention discloses a light-emitting device and a preparation method thereof, the light-emitting device comprises an N-type silicon substrate, a black phosphorus layer located on the N-type silicon substrate and electrodes, the electrodes comprise a first electrode electrically connected with the N-type silicon substrate and a second electrode electrically connected with the black phosphorus layer, and the black phosphorus layer and the N-type silicon substrate form a heterojunction. The N-type silicon substrate is used as a platform, the black phosphorus layer is integrated on the N-type silicon substrate to obtain the black phosphorus-N-type silicon heterojunction structure light-emitting device, a large light-emitting area and high light output power can be achieved, a feasible way is provided for achieving an on-chip light-emitting device and a silicon-based photoelectric integrated system, and wide application prospects are achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor devices, and particularly relates to a light-emitting device and a preparation method thereof. BACKGROUND

[0002] Mid-infrared (MID-IR) light-emitting devices have important application values in the fields of gas molecule characteristic absorption spectrum identification, environmental and industrial gas detection, non-contact temperature measurement, infrared communication and biomedical imaging. At present, the mid-infrared light-emitting devices mainly adopt III-V or II-VI semiconductor heterostructures (such as InAs / GaSb, InAs / GaAsSb, etc.) or epitaxial structures based on quantum wells / quantum dots.

[0003] However, although the mid-infrared light-emitting devices in the prior art can realize high-efficiency light emission, they usually need expensive epitaxial equipment and need to be grown under high-temperature conditions, and have poor compatibility with silicon-based CMOS processes, which limits the integration with large-scale silicon optoelectronic platforms and low-cost manufacturing.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a light-emitting device and a preparation method thereof. SUMMARY

[0005] The purpose of the present application is to provide a light-emitting device and a preparation method thereof, which can realize high light output power.

[0006] In order to achieve the above-mentioned purpose, the technical scheme provided by an embodiment of the present application is as follows:

[0007] A light-emitting device, comprising an N-type silicon substrate, a black phosphorus layer located on the N-type silicon substrate, and an electrode, the electrode comprising a first electrode electrically connected with the N-type silicon substrate and a second electrode electrically connected with the black phosphorus layer, the black phosphorus layer and the N-type silicon substrate forming a black phosphorus-N-type silicon heterojunction structure.

[0008] In an embodiment, the light-emitting device further comprises a hexagonal boron nitride layer, the hexagonal boron nitride layer being located at least on the black phosphorus layer.

[0009] In an embodiment, the light-emitting device comprises a silicon oxide layer located on the N-type silicon substrate, a window penetrating the N-type silicon substrate is provided on the silicon oxide layer, and the black phosphorus layer is located at least partially on the N-type silicon substrate in the window.

[0010] In an embodiment, the second electrode is located on the silicon oxide layer, and the black phosphorus layer is partially located on the second electrode.

[0011] In an embodiment, the light-emitting device further comprises a hexagonal boron nitride layer, the hexagonal boron nitride layer covering the silicon oxide layer, the black phosphorus layer and the second electrode.

[0012] In an embodiment, the first electrode is electrically connected to a negative pole of an external power source, and the second electrode is electrically connected to a positive pole of the external power source.

[0013] Another embodiment of the present application provides the technical scheme as follows:

[0014] A preparation method of a light-emitting device, the preparation method comprising the following steps:

[0015] Providing an N-type silicon substrate;

[0016] Preparing a black phosphorus layer on the N-type silicon substrate, the black phosphorus layer and the N-type silicon substrate forming a black phosphorus-N-type silicon heterojunction structure;

[0017] Preparing a first electrode electrically connected to the N-type silicon substrate and a second electrode electrically connected to the black phosphorus layer.

[0018] In an embodiment, the step of preparing the black phosphorus layer on the N-type silicon substrate further comprises:

[0019] Providing a hexagonal boron nitride crystal;

[0020] Preparing a hexagonal boron nitride layer on the hexagonal boron nitride crystal by a mechanical exfoliation process;

[0021] Transferring the prepared hexagonal boron nitride layer to the black phosphorus layer by a dry transfer process.

[0022] In an embodiment, the N-type silicon substrate is provided with a silicon oxide layer, and the step of providing the N-type silicon substrate comprises:

[0023] Preparing a patterned photoresist layer on the silicon oxide layer;

[0024] Etching the silicon oxide layer with the patterned photoresist layer as a mask to form a window penetrating through the N-type silicon substrate.

[0025] In an embodiment, the step of preparing the black phosphorus layer on the N-type silicon substrate comprises:

[0026] Preparing a black phosphorus crystal by a chemical vapor deposition process;

[0027] Preparing a black phosphorus layer on the black phosphorus crystal by a mechanical exfoliation process;

[0028] Transferring the prepared black phosphorus layer to the N-type silicon substrate by a dry transfer process.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] This invention creates a light-emitting device with a large light-emitting area and high light output power by forming a black phosphorus-N-type silicon heterojunction structure with black phosphorus and an N-type silicon substrate.

[0031] This invention uses a silicon substrate as a platform to fabricate high-quality light-emitting devices on a silicon substrate through a simple fabrication process. It has good process compatibility and high structural stability, and can be directly integrated with existing silicon photonics process systems. It provides a feasible way to realize on-chip mid-infrared light sources and silicon-based optoelectronic integrated systems, and has broad application prospects. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the light-emitting device in Embodiment 1 of the present invention;

[0034] Figure 2 This is a current-voltage (IV) curve of the light-emitting device in Embodiment 1 of the present invention;

[0035] Figure 3 This is a comparison chart of the photoluminescence intensity of black phosphorus measured at room temperature and 78K in Example 1 of the present invention;

[0036] Figure 4 This is an electroluminescence diagram of the light-emitting device in Embodiment 1 of the present invention;

[0037] Figure 5 This is a polarization electroluminescence diagram of the light-emitting device in Embodiment 1 of the present invention.

[0038] Explanation of key figure labels:

[0039] 11-N-type silicon substrate, 12-black phosphorus layer, 201-first electrode, 202-second electrode, 30-silicon oxide layer, 40-hexagonal boron nitride layer. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0041] The present invention discloses a light-emitting device, which includes an N-type silicon substrate, a black phosphorus layer located on the N-type silicon substrate, and electrodes. The electrodes include a first electrode electrically connected to the N-type silicon substrate and a second electrode electrically connected to the black phosphorus layer. The black phosphorus layer and the N-type silicon substrate form a black phosphorus-N-type silicon heterojunction structure.

[0042] The present invention also discloses a method for manufacturing a light-emitting device, which includes the following steps:

[0043] Provide an N-type silicon substrate;

[0044] Prepare a black phosphorus layer on the N-type silicon substrate, and the black phosphorus layer and the N-type silicon substrate form a black phosphorus-N-type silicon heterojunction structure;

[0045] Prepare a first electrode electrically connected to the N-type silicon substrate and a second electrode electrically connected to the black phosphorus layer.

[0046] The following further illustrates the present invention with specific examples.

[0047] Example 1:

[0048] Refer Figure 1 As shown, the light-emitting device in this example includes an N-type silicon substrate 11, a black phosphorus layer 12 located on the N-type silicon substrate, and electrodes. The electrodes include a first electrode 201 electrically connected to the N-type silicon substrate 11 and a second electrode 202 electrically connected to the black phosphorus layer 12. The black phosphorus layer 12 and the N-type silicon substrate 11 form a black phosphorus-N-type silicon heterojunction structure.

[0049] Specifically, a silicon oxide layer 30 is provided on the N-type silicon substrate 11 of this example, and a window penetrating through the N-type silicon substrate 11 is provided on the silicon oxide layer 30.

[0050] More specifically, the thickness of the silicon oxide layer 30 in this example is 100 nm, and a part of the black phosphorus layer 12 is located on the N-type silicon substrate 11 within the window to contact the N-type silicon substrate 11, forming a black phosphorus-N-type silicon heterojunction structure.

[0051] Furthermore, the majority carriers in the black phosphorus layer 12 are holes, that is, the conduction type of the black phosphorus layer 12 is P-type.

[0052] Specifically, the first electrode 201 in this example is located on the surface of the N-type silicon substrate 11 away from the black phosphorus layer 12, and the second electrode 202 is located on the silicon oxide layer 30. The black phosphorus layer 12 includes a contact portion located on the N-type silicon substrate 11 within the window and an extension portion extending outward from the contact portion to the second electrode 202. The second electrode 202 contacts the extension portion to achieve electrical connection with the black phosphorus layer 12.

[0053] More specifically, the first electrode is electrically connected to the negative terminal of the external power supply, and the second electrode is electrically connected to the positive terminal of the external power supply, so that the P-type conductive black phosphorus layer is electrically connected to the positive terminal of the external power supply, and the N-type silicon substrate is electrically connected to the negative terminal of the external power supply, thereby realizing the conduction of the black phosphorus-N-type silicon heterojunction structure.

[0054] Furthermore, the light-emitting device in this embodiment also includes a hexagonal boron nitride (h-BN) layer 40, which is located at least on the black phosphorus layer 12. As a protective layer, the hexagonal boron nitride layer provides physical protection to the black phosphorus layer while effectively isolating it from the influence of water molecules and oxygen in the air, thus maximizing and enhancing the intrinsic superior performance of the black phosphorus layer.

[0055] Specifically, in this embodiment, the hexagonal boron nitride layer 40 also covers the second electrode 202.

[0056] The method for fabricating the light-emitting device in this embodiment includes the following steps:

[0057] S1, Provides an N-type silicon substrate.

[0058] In this embodiment, an N-type silicon substrate is provided with a silicon oxide layer, the thickness of which is 100 nm.

[0059] Specifically, this step includes:

[0060] 1. A patterned photoresist layer is prepared on a silicon oxide layer.

[0061] AZ5214 photoresist was spin-coated onto a silicon oxide layer, and a patterned photoresist layer was formed on the silicon oxide layer after standard photolithography.

[0062] 2. Using a patterned photoresist layer as a mask, the silicon oxide layer is etched to form a window that extends through to the N-type silicon substrate.

[0063] Specifically, using a patterned photoresist layer as a mask, the silicon oxide layer is etched using a reactive ion etching (RIE) process to achieve pattern transfer and form a window on the silicon oxide layer that extends to the N-type silicon substrate.

[0064] S2. A black phosphorus layer is prepared on an N-type silicon substrate, and the black phosphorus layer and the N-type silicon substrate form a black phosphorus-N-type silicon heterojunction structure.

[0065] Specifically, this step includes:

[0066] 1. Black phosphorus crystals were prepared by chemical vapor deposition (CVD).

[0067] 2. The black phosphorus layer is peeled off from the black phosphorus crystals using a mechanical peeling process;

[0068] 3. Transfer the exfoliated black phosphorus layer onto the N-type silicon substrate through a dry transfer process.

[0069] S4. Fabricate a first electrode electrically connected to the N-type silicon substrate and a second electrode electrically connected to the black phosphorus layer.

[0070] Specifically, in this embodiment, the first electrode is fabricated on the surface of the N-type silicon substrate away from the black phosphorus layer. Before the transfer of the black phosphorus layer is completed, the second electrode is first fabricated on the silicon oxide layer, and the second electrode is disposed adjacent to the window. After the fabrication of the second electrode is completed, the transfer of the black phosphorus layer is then carried out, so that the black phosphorus layer includes a contact portion on the N-type silicon substrate within the window and an extension portion on the second electrode.

[0071] In addition, the fabrication method of this embodiment further includes fabricating a hexagonal boron nitride layer as a protective layer, including the following steps:

[0072] 1. Provide a hexagonal boron nitride crystal;

[0073] 2. Exfoliate the hexagonal boron nitride layer from the hexagonal boron nitride crystal through a mechanical exfoliation process;

[0074] 3. Transfer the exfoliated hexagonal boron nitride layer onto the black phosphorus layer through a dry transfer process.

[0075] Specifically, the hexagonal boron nitride layer in this embodiment covers the black phosphorus layer, the second electrode, and the silicon oxide layer.

[0076] Refer Figure 2 As shown, the electrical performance of the fabricated light-emitting device in this embodiment is tested at room temperature. The test results show that the current-voltage (I-V) curve of the light-emitting device exhibits significant non-linear rectification characteristics. Under forward bias, the current increases exponentially with the increase of voltage, while in the reverse bias range (-5V to 0V), the current remains at a low cut-off level. The above typical diode rectification behavior indicates that a high-quality heterojunction interface is formed between the P-type conductive black phosphorus layer and the N-type silicon substrate, having good unilateral conductivity.

[0077] Currently, traditional mid-infrared light-emitting devices mainly adopt III-V or II-VI semiconductor heterostructures or epitaxial structures based on quantum wells / quantum dots. However, due to their complex fabrication processes and high costs, it is difficult to achieve wide promotion and application. In recent years, two-dimensional materials have become a research hotspot due to their unique tunable bandgaps, strong light absorption and emission characteristics, and the potential of van der Waals interfacial coupling with various substrates. As a layered two-dimensional material, black phosphorus (BP) has a tunable bandgap ranging from ~0.3 eV (thick layer) to ~2.0 eV (single layer), covering the near-infrared to mid-infrared bands. At the same time, black phosphorus is sensitive to photoelectric response and has a high carrier mobility, so it is regarded as a candidate material for realizing silicon-based mid-infrared light-emitting devices.

[0078] As shown Figure 3 in the figure, the photoluminescence (PL) spectra of black phosphorus materials at room temperature (RT) and low temperature (78 K) are compared. The spectra cover the mid-infrared band of 2500 nm to 4500 nm. The test results show that compared with the room temperature environment, at a low temperature of 78 K, the intensity of the PL emission peak of black phosphorus materials is significantly enhanced, and the peak shape is sharper. This indicates that the low temperature environment effectively suppresses the non-radiative recombination process, thereby enhancing the radiative emission efficiency of black phosphorus materials.

[0079] On this basis, as shown Figure 4 in the figure, the electroluminescence (EL) performance of the light-emitting device in this embodiment is tested at a low temperature of 77 K. The spectrum records the changes in the emission spectra of the light-emitting device under different injection conditions, where the values shown in the legend represent the applied voltage (V) and the corresponding injection current (mA). The test results show that as the injection voltage increases from 9.6 V to 21.1 V (corresponding to the current increasing from 0.79 mA to 11.98 mA), the intensity of the EL spectrum of the device in the 3000 nm to 4500 nm band shows a monotonically increasing trend. The significant enhancement of the device's light emission intensity is positively correlated with the increase in the injected carrier concentration, demonstrating that the electroluminescence mechanism of the light-emitting device in this embodiment originates from the recombination of carriers in the heterojunction region, and the light emission intensity can be effectively regulated by the injection current.

[0080] As shown Figure 5As shown, to characterize the polarization characteristics of the light-emitting device in this embodiment, the polarization-resolved electroluminescence intensity (EL) of the device was tested under a fixed bias voltage of 14.7V and an injection current of 4.62mA. In polar coordinates, the EL intensity of the light-emitting device in this embodiment exhibits a clear figure-eight bilobed distribution pattern as a function of the polarization angle. This result indicates that the light emitted by the light-emitting device in this embodiment has significant linear polarization characteristics and exhibits strong anisotropy. This characteristic is mainly attributed to the anisotropy of the black phosphorus crystal structure, giving the light-emitting device in this embodiment specific application potential in the field of polarized light detection and emission.

[0081] As can be seen from the above technical solution, the present invention has the following beneficial effects:

[0082] This invention creates a light-emitting device with a large light-emitting area and high light output power by forming a black phosphorus-N-type silicon heterojunction structure with black phosphorus and an N-type silicon substrate.

[0083] This invention uses a silicon substrate as a platform to fabricate high-quality light-emitting devices on a silicon substrate through a simple fabrication process. It has good process compatibility and high structural stability, and can be directly integrated with existing silicon photonics process systems. It provides a feasible way to realize on-chip mid-infrared light sources and silicon-based optoelectronic integrated systems, and has broad application prospects.

[0084] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0085] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A light-emitting device, characterized in that, The light-emitting device includes an N-type silicon substrate, a black phosphorus layer on the N-type silicon substrate, and electrodes. The electrodes include a first electrode electrically connected to the N-type silicon substrate and a second electrode electrically connected to the black phosphorus layer. The black phosphorus layer and the N-type silicon substrate form a black phosphorus-N-type silicon heterojunction structure.

2. The light-emitting device according to claim 1, characterized in that, The light-emitting device further includes a hexagonal boron nitride layer, which is located at least on the black phosphorus layer.

3. The light-emitting device according to claim 1, characterized in that, The light-emitting device includes a silicon oxide layer on an N-type silicon substrate, the silicon oxide layer having a window extending through the N-type silicon substrate, and the black phosphorus layer being at least partially located on the N-type silicon substrate within the window.

4. The light-emitting device according to claim 3, characterized in that, The second electrode is located on the silicon oxide layer, and the black phosphorus layer is partially located on the second electrode.

5. The light-emitting device according to claim 4, characterized in that, The light-emitting device further includes a hexagonal boron nitride layer, which covers the silicon oxide layer, the black phosphorus layer, and the second electrode.

6. The light-emitting device according to claim 1, characterized in that, The first electrode is electrically connected to the negative terminal of the external power supply, and the second electrode is electrically connected to the positive terminal of the external power supply.

7. A method for fabricating a light-emitting device, characterized in that, The preparation method includes the following steps: Provide N-type silicon substrates; A black phosphorus layer is prepared on an N-type silicon substrate, and the black phosphorus layer and the N-type silicon substrate form a black phosphorus-N-type silicon heterojunction structure. A first electrode electrically connected to an N-type silicon substrate and a second electrode electrically connected to a black phosphorus layer are prepared.

8. The method for preparing a light-emitting device according to claim 7, characterized in that, The step of preparing a black phosphorus layer on an N-type silicon substrate also includes: Hexagonal boron nitride crystals are available; The hexagonal boron nitride layer was peeled off from the hexagonal boron nitride crystal using a mechanical peeling process. The stripped hexagonal boron nitride layer is transferred to the black phosphorus layer using a dry transfer process.

9. The method for fabricating a light-emitting device according to claim 7, characterized in that, The N-type silicon substrate has a silicon oxide layer, and the step of providing the N-type silicon substrate includes: A patterned photoresist layer is prepared on a silicon oxide layer; The silicon oxide layer is etched using a patterned photoresist layer as a mask to form a window that extends into the N-type silicon substrate.

10. The method for fabricating a light-emitting device according to claim 7 or 9, characterized in that, The fabrication of a black phosphorus layer on an N-type silicon substrate includes: Black phosphorus crystals were prepared by chemical vapor deposition. The black phosphorus layer is peeled off from the black phosphorus crystals using a mechanical peeling process. The stripped black phosphorus layer is transferred onto an N-type silicon substrate using a dry transfer process.

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