Organic diode and manufacturing method thereof

Abstract

The invention relates to the technical field of semiconductor manufacturing, and provides an organic diode and a manufacturing method thereof, and the organic diode comprises an inorganic semiconductor substrate of a first conduction type; the at least two layers of epitaxial structures of the first conduction type are positioned on the first side of the inorganic semiconductor substrate of the first conduction type and comprise an inorganic semiconductor epitaxial layer of a first doping concentration positioned on the first side of the inorganic semiconductor substrate of the first conduction type; the inorganic semiconductor epitaxial layer with the second doping concentration is positioned on the inorganic semiconductor epitaxial layer with the first doping concentration; the first doping concentration is higher than the second doping concentration; an organic semiconductor layer of a second conduction type is arranged on the inorganic semiconductor epitaxial layer of the second doping concentration; the second side of the inorganic semiconductor substrate of the first conductive type is provided with a first electrode, and the first side of the organic semiconductor layer of the second conductive type is provided with a second electrode. The organic diode is high in voltage resistance, low in electric leakage and high in rectification ratio.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to an organic diode and its manufacturing method. Background Technology

[0002] In related technologies, organic diodes typically employ an all-organic structure, or simply deposit organic semiconductors directly onto a heavily doped inorganic semiconductor substrate to form a heterojunction. However, such structures have limitations: on the one hand, organic materials themselves have low dielectric constants, poor carrier mobility, and are difficult to withstand high electric fields, resulting in generally low reverse breakdown voltage; on the other hand, when the organic layer is in direct contact with a heavily doped inorganic substrate, the depletion region under reverse bias is extremely narrow due to the high doping concentration, causing the peak electric field to be highly concentrated near the organic / inorganic interface. This strong electric field not only induces direct carrier tunneling but also activates interface state defects, forming trap-assisted leakage channels, resulting in problems such as large reverse leakage current, low breakdown voltage, and poor rectification ratio. Furthermore, existing organic / inorganic heterojunction diodes typically fabricate back electrodes directly on lightly doped or poorly doped inorganic semiconductor substrates. Due to insufficient substrate doping concentration, it is difficult to form a good ohmic contact with the metal electrode, and a Schottky barrier easily forms between the substrate and the metal electrode, introducing a large series resistance and further degrading device performance. Therefore, existing technologies struggle to balance high voltage withstand, low leakage current, and low contact resistance, failing to meet the demands of high-voltage rectification or power applications.

[0003] Therefore, there is an urgent need for an organic diode and its manufacturing method to improve the above problems. Summary of the Invention

[0004] This invention provides an organic diode and a method for manufacturing the same. This invention is used to provide an organic diode with high withstand voltage, low leakage current, and high rectification ratio.

[0005] According to a first aspect of the present invention, an organic diode is provided, comprising: an inorganic semiconductor substrate of a first conductivity type; at least two epitaxial structures of the first conductivity type, the at least two epitaxial structures of the first conductivity type being located on a first side of the inorganic semiconductor substrate of the first conductivity type; the at least two epitaxial structures of the first conductivity type comprising: an inorganic semiconductor epitaxial layer of a first doping concentration located on the first side of the inorganic semiconductor substrate of the first conductivity type, and an inorganic semiconductor epitaxial layer of a second doping concentration located on the inorganic semiconductor epitaxial layer of the first doping concentration; the first doping concentration being higher than the second doping concentration; an organic semiconductor layer of a second conductivity type located on the inorganic semiconductor epitaxial layer of the second doping concentration; the first conductivity type and the second conductivity type being opposite; and a first electrode located on the first conductivity type... The second side of the inorganic semiconductor substrate; the second electrode, located on the first side of the organic semiconductor layer of the second conductivity type; the first side and the second side are opposite sides; when a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode, the organic diode is in a reverse bias state; the inorganic semiconductor epitaxial layer with a second doping concentration is used to reduce the internal peak electric field intensity under reverse bias; the inorganic semiconductor epitaxial layer with a first doping concentration is used to reduce the contact resistance between the inorganic semiconductor substrate of the first conductivity type and the first electrode; the interface between the inorganic semiconductor epitaxial layer with a second doping concentration and the organic semiconductor layer of the second conductivity type forms a heterojunction, which suppresses the direct tunneling of charge carriers and the conduction path assisted by interface defects due to the reduction of the peak electric field intensity, thereby reducing the reverse leakage current of the organic diode and improving the reverse breakdown voltage and rectification ratio.

[0006] In one embodiment, the inorganic semiconductor substrate of the first conductivity type has a band gap greater than 2.3 eV.

[0007] In one embodiment, the inorganic semiconductor substrate of the first conductivity type is made of at least one of silicon carbide, gallium nitride, gallium oxide, and aluminum nitride.

[0008] In one embodiment, the organic semiconductor layer of the second conductivity type is made of small organic molecules with a molecular weight of less than 2000 g / mol or a diketopyrrolopyrrolo-thiophenothiophene copolymer.

[0009] In one embodiment, the small organic molecule includes at least one of 2,7-dioctylbenzothiophene (C8-BTBT), decyl-substituted dinaphthophene (C10-DNTT), and pentaphenyl.

[0010] In one embodiment, the thickness of the inorganic semiconductor epitaxial layer with the second doping concentration ranges from 1 μm to 1000 μm.

[0011] In one embodiment, the first electrode and the second electrode are made of at least one of gold and titanium.

[0012] In one embodiment, the at least two layers of epitaxial structure of the first conductivity type further include: at least one transition epitaxial layer located between an inorganic semiconductor epitaxial layer with a first doping concentration and an inorganic semiconductor epitaxial layer with a second doping concentration, wherein the doping concentration of the transition epitaxial layer is lower than the first doping concentration and higher than the second doping concentration.

[0013] According to a second aspect of the present invention, a method for manufacturing an organic diode is provided, comprising: providing an inorganic semiconductor substrate of a first conductivity type; sequentially epitaxially growing an inorganic semiconductor epitaxial layer with a first doping concentration and an inorganic semiconductor epitaxial layer with a second doping concentration on a first side of the inorganic semiconductor substrate of the first conductivity type; wherein the first doping concentration is higher than the second doping concentration; forming an organic semiconductor layer of a second conductivity type on the inorganic semiconductor epitaxial layer with the second doping concentration; wherein the first conductivity type and the second conductivity type are opposite; fabricating a first electrode on a second side of the inorganic semiconductor substrate of the first conductivity type, and fabricating a second electrode on a first side of the organic semiconductor layer of the second conductivity type; wherein the first side and the second side are opposite sides.

[0014] In one embodiment, forming an organic semiconductor layer of a second conductivity type on an inorganic semiconductor epitaxial layer with a second doping concentration includes: depositing an organic small molecule with a molecular weight of less than 2000 g / mol or a diketopyrrolopyrrolo-thiophenothiophene copolymer as an organic semiconductor layer of the second conductivity type on the inorganic semiconductor epitaxial layer with a second doping concentration by organic molecular beam evaporation.

[0015] In one embodiment, a second electrode is prepared on a first side of an organic semiconductor layer of a second conductivity type, comprising: sputtering at least one of gold and titanium as a second electrode on the organic semiconductor layer of the second conductivity type by physical vapor deposition.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: a heterojunction structure is constructed by forming an inorganic semiconductor epitaxial layer with a first doping concentration and an inorganic semiconductor epitaxial layer with a second doping concentration on a first side of an inorganic semiconductor substrate of a first conductivity type, and forming an organic semiconductor layer of a second conductivity type thereon. When a positive voltage is applied to the first electrode and a negative voltage is applied to the second electrode, the diode is in a reverse bias state. In this state, since the carrier concentration of the inorganic semiconductor epitaxial layer with the second doping concentration is much lower than that of the substrate and the inorganic semiconductor epitaxial layer with the first doping concentration, the depletion region mainly extends within the inorganic semiconductor epitaxial layer with the second doping concentration; the electric field strength in the semiconductor is proportional to the doping concentration, so the low doping characteristic makes the electric field distribution in this region more gradual, thereby effectively reducing the internal peak electric field strength. The reduction of the peak electric field directly suppresses two main reverse leakage mechanisms: one is direct carrier tunneling, and the other is the trap state conduction path assisted by interface defects. As a result, the reverse leakage current is significantly reduced, while the reverse breakdown voltage of the diode is increased, and the withstand voltage capability is significantly enhanced. Since the forward conduction characteristics are mainly determined by the heterojunction barrier and are basically unaffected, the rectification ratio, i.e., the ratio of forward current to reverse current, is significantly improved. In summary, this structural design optimizes the electric field distribution from a physical mechanism by using the epitaxial layer with the second doping concentration as the main withstand voltage region, achieving a comprehensive performance advantage of high withstand voltage, low leakage current, and high rectification ratio without sacrificing forward performance. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an organic diode according to an exemplary embodiment.

[0018] Figure 2 This is a schematic diagram of a flowchart illustrating a method for manufacturing an organic diode according to an exemplary embodiment.

[0019] Figure 3 This is a schematic diagram illustrating a structure for forming an inorganic semiconductor epitaxial layer with a second doping concentration, according to another exemplary embodiment.

[0020] Figure 4 This is a schematic diagram of a structure for forming an organic semiconductor layer of a second conductivity type, according to another exemplary embodiment.

[0021] Figure 5 This is a schematic diagram illustrating the current density-voltage characteristic curve and rectification ratio of an organic diode in a low bias range, according to an exemplary embodiment.

[0022] Figure 6 This is a schematic diagram of the current density-voltage characteristic curve of an organic diode under high reverse bias, according to another exemplary embodiment.

[0023] Explanation of the reference numerals in the figure: 1. An inorganic semiconductor substrate of a first conductivity type; 2. An inorganic semiconductor epitaxial layer with a first doping concentration; 3. An inorganic semiconductor epitaxial layer with a second doping concentration; 4. An organic semiconductor layer of a second conductivity type; 5. A first electrode; 6. A second electrode. Detailed Implementation

[0024] Unless otherwise defined, the technical or scientific terms used in this specification should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. Specific embodiments of the invention will be described below with reference to the accompanying drawings. It should be noted that, in order to provide a concise description, this specification cannot provide a detailed description of all features of the actual embodiments. Without departing from the spirit and scope of the invention, those skilled in the art can make modifications and substitutions to the embodiments of the invention, and the resulting embodiments are also within the protection scope of the invention.

[0025] In related technologies, organic diodes, as an important component of flexible electronics and optoelectronics, have shown significant advantages in terms of material flexibility, solution processability, and manufacturing cost. However, in practical applications, they still face key bottlenecks such as weak withstand voltage, large reverse leakage current, and low rectification ratio. These problems mainly stem from the intrinsic limitations of organic semiconductor materials and the complexity of their interface physical processes. On the one hand, organic materials typically have low carrier mobility and high defect state density, which easily induces direct carrier tunneling and defect-assisted carrier injection under reverse bias, leading to significant reverse leakage current. On the other hand, the weak van der Waals forces between organic molecules make it difficult to precisely control the energy level arrangement at the heterojunction, further exacerbating non-ideal transport behavior. In addition, organic materials have poor stability under strong electric fields, and reverse bias may trigger interfacial chemical reactions or material degradation, forming local micro-conductive channels, causing diode short circuits or even permanent failure. At the same time, bidirectional carrier injection and space charge accumulation also severely degrade rectification characteristics, especially under flexible stress conditions such as high temperature or mechanical bending, where diode performance degradation is more significant.

[0026] Organic diodes generally have poor reverse bias tolerance, easily experiencing performance degradation or even irreversible physical damage even at relatively low reverse voltages. This directly limits their feasibility for use in AC circuits or applications requiring reverse voltage tolerance. Furthermore, high reverse leakage current not only increases static power consumption, hindering the design of low-power devices, but also introduces significant noise in applications such as photoelectric detection, reducing the signal-to-noise ratio and detection sensitivity, making weak light detection difficult. The rectification ratio is a key parameter for measuring the unidirectional conductivity of a diode. Organic diodes typically exhibit a low rectification ratio, meaning the ratio of forward current to reverse leakage current is insufficient, thus weakening their rectification efficiency and signal processing capabilities in circuits. These shortcomings collectively affect the operational stability and lifespan of organic diodes, especially under high temperature or flexible stress conditions, where performance degradation is more pronounced, making it difficult to meet the stringent reliability and durability requirements of many commercial applications.

[0027] like Figure 1 As shown, a first embodiment of the present invention provides an organic diode, comprising: an inorganic semiconductor substrate 1 of a first conductivity type; at least two epitaxial structures of the first conductivity type, the at least two epitaxial structures of the first conductivity type being located on a first side of the inorganic semiconductor substrate 1 of the first conductivity type; the at least two epitaxial structures of the first conductivity type comprising: an inorganic semiconductor epitaxial layer 2 of a first doping concentration located on the first side of the inorganic semiconductor substrate 1 of the first conductivity type, and an inorganic semiconductor epitaxial layer 3 of a second doping concentration located on the inorganic semiconductor epitaxial layer 2 of the first doping concentration; the first doping concentration is higher than the second doping concentration; an organic semiconductor layer 4 of a second conductivity type, the organic semiconductor layer 4 of the second conductivity type being located on the inorganic semiconductor epitaxial layer 3 of the second doping concentration; the first conductivity type and the second conductivity type being opposite; and a first electrode 5, the first electrode 5 being located on the inorganic semiconductor epitaxial layer 3 of the first conductivity type. The second side of the organic semiconductor substrate 1; the second electrode 6, the second electrode 6 is located on the first side of the organic semiconductor layer 4 of the second conductivity type; the first side and the second side are opposite sides; when a positive voltage is applied to the first electrode 5 and a negative voltage is applied to the second electrode 6, the organic diode is in a reverse bias state; the inorganic semiconductor epitaxial layer 3 with a second doping concentration is used to reduce the internal peak electric field intensity under the reverse bias state; the inorganic semiconductor epitaxial layer 2 with a first doping concentration is used to reduce the contact resistance between the inorganic semiconductor substrate 1 of the first conductivity type and the first electrode 5; the interface between the inorganic semiconductor epitaxial layer 3 with a second doping concentration and the organic semiconductor layer 4 of the second conductivity type forms a heterojunction, which suppresses the direct tunneling of charge carriers and the conduction path assisted by interface defects due to the reduction of the peak electric field intensity, thereby reducing the reverse leakage current of the organic diode and improving the reverse breakdown voltage and rectification ratio.

[0028] In some examples, the first conductivity type is N-type and the second conductivity type is P-type. In other examples, the first conductivity type is P-type and the second conductivity type is N-type.

[0029] In one embodiment, the inorganic semiconductor substrate 1 of the first conductivity type has a band gap greater than 2.3 eV.

[0030] In some specific embodiments, the diode bandgap refers to the energy difference between the top of the valence band and the bottom of the conduction band in a semiconductor material, measured in electron volts (eV). It determines the minimum energy threshold for photon absorption and the intrinsic carrier concentration. A larger bandgap results in a lower intrinsic carrier concentration and a higher breakdown electric field strength, thus providing stronger high-voltage withstand capability. When the substrate bandgap exceeds 2.3 eV, its intrinsic carrier concentration is significantly lower than that of silicon in conventional technologies. Under reverse bias, it is less likely to generate electron-hole pairs due to thermal excitation, effectively suppressing intrinsic leakage current. Simultaneously, wide-bandgap materials have a higher critical breakdown electric field, typically 5–10 times that of silicon, allowing the depletion region to withstand a stronger electric field without avalanche breakdown. Therefore, using an inorganic semiconductor with a first conductivity type and a band gap greater than 2.3 eV as a substrate not only improves the overall voltage withstand level of the diode, but also further optimizes the electric field distribution in conjunction with the epitaxial layer with a second doping concentration, thereby significantly reducing the reverse leakage current, increasing the reverse breakdown voltage, and ultimately enhancing the rectification performance and operational reliability of the organic diode.

[0031] In some embodiments, the inorganic semiconductor substrate 1 of the first conductivity type is made of at least one of silicon carbide, gallium nitride, gallium oxide, and aluminum nitride.

[0032] In some specific embodiments, the inorganic semiconductor substrate 1 of the first conductivity type is made of silicon carbide, which has a high critical breakdown electric field and high thermal conductivity, enabling it to withstand high voltage and high power applications.

[0033] In some embodiments, the organic semiconductor layer 4 of the second conductivity type is made of small organic molecules with a molecular weight of less than 2000 g / mol or diketopyrrolopyrrolo-thiophenothiophene copolymer.

[0034] In one specific embodiment, the small organic molecule includes at least one of 2,7-dioctylbenzothiophene, decyl-substituted dinaphthothiophene, and pentabenzene.

[0035] In some specific embodiments, 2,7-dioctylbenzothiophene possesses a highly ordered π-conjugated molecular structure and strong intermolecular stacking ability, achieving a hole mobility exceeding 10 cm² / (V•s) in the thin-film state, significantly superior to traditional organic semiconductors. This high mobility not only enhances the forward conduction capability of the diode but also reduces the series resistance, contributing to improved rectification efficiency. Simultaneously, the two octyl groups (–C8H) on the side chains of the 2,7-dioctylbenzothiophene molecule... 17 This material possesses excellent solubility, being soluble in various nonpolar organic solvents (such as chloroform and toluene), thus enabling compatibility with low-cost, large-area solution processing techniques (such as spin coating, inkjet printing, or blade coating), avoiding reliance on high-vacuum evaporation equipment. More importantly, this material maintains high crystallinity and electrical properties when deposited on flexible substrates, exhibiting excellent mechanical flexibility. Therefore, in the organic / inorganic heterojunction diode of this invention, the 2,7-dioctylbenzothiophene diode not only provides high carrier transport capability as a highly efficient second-conductivity type semiconductor, but also, through its solution processability and flexibility, enables the diode to combine the advantages of high performance, low manufacturing cost, and suitability for flexible electronic integration.

[0036] In some embodiments, the thickness of the inorganic semiconductor epitaxial layer 3 with the second doping concentration ranges from 1 μm to 1000 μm.

[0037] In some examples, the thickness of the inorganic semiconductor epitaxial layer 3 with the second doping concentration is 10 μm.

[0038] It is worth noting that the breakdown voltage of the inorganic semiconductor epitaxial layer 3 with the second doping concentration is positively correlated with its thickness: the greater the thickness, the wider the space for the depletion region to expand, and the lower the internal peak electric field, thereby significantly improving the reverse breakdown voltage and overall breakdown voltage of the diode.

[0039] In some embodiments, the first electrode 5 and the second electrode 6 are made of at least one of gold and titanium.

[0040] In some specific embodiments, gold has a high work function, stable chemical properties, and excellent conductivity. It also forms a good hole injection barrier match with organic semiconductors of the second conductivity type, making it particularly suitable as the second electrode 6 in contact with the organic semiconductor layer 4 of the second conductivity type. This effectively reduces contact resistance and improves forward conduction performance. Titanium, on the other hand, has a lower work function but excellent adhesion to inorganic semiconductor surfaces and ohmic contact formation capabilities. Especially when deposited as the first electrode 5 on the second side of the inorganic semiconductor substrate 1 of the first conductivity type, it can achieve low-resistance ohmic contacts through interfacial reactions or doping activation, significantly reducing series resistance.

[0041] Furthermore, both gold and titanium can be precisely deposited using mature processes such as physical vapor deposition or electron beam evaporation, making them compatible with the manufacturing process of this invention. In some embodiments, a Ti / Au stacked structure can also be employed, such as first depositing a thin layer of titanium to enhance adhesion, and then covering it with gold to improve conductivity and stability, further optimizing the overall electrode performance. Therefore, selecting gold, titanium, or a combination thereof as electrode materials not only meets the requirement of efficient carrier injection / extraction but also takes into account process feasibility, interface stability, and diode reliability.

[0042] In some embodiments, the at least two epitaxial structures of the first conductivity type further include: at least one transition epitaxial layer (not shown) located between the inorganic semiconductor epitaxial layer 2 with the first doping concentration and the inorganic semiconductor epitaxial layer 3 with the second doping concentration, wherein the doping concentration of the transition epitaxial layer is lower than the first doping concentration and higher than the second doping concentration.

[0043] It is worth noting that the doping concentration of the transition epitaxial layer is designed to be between the first and second doping concentrations, thus forming a gentle doping gradient from high to low in the vertical direction. This gradient doping structure helps to alleviate band discontinuities caused by abrupt changes in doping concentration, optimizes the electric field distribution in the depletion region, avoids local electric field concentration, and further suppresses carrier tunneling and defect-assisted leakage paths.

[0044] like Figure 2 As shown, a second embodiment of the present invention provides a method for manufacturing an organic diode, used in the organic diode of the above embodiment, comprising the following steps S1-S4: Step S1, provide an inorganic semiconductor substrate 1 of a first conductivity type.

[0045] Step S2: On the first side of the inorganic semiconductor substrate 1 of the first conductivity type, an inorganic semiconductor epitaxial layer 2 with a first doping concentration and an inorganic semiconductor epitaxial layer 3 with a second doping concentration are epitaxially grown sequentially; the first doping concentration is higher than the second doping concentration.

[0046] Step S3: An organic semiconductor layer 4 of a second conductivity type is formed on the inorganic semiconductor epitaxial layer 3 with a second doping concentration; the first conductivity type and the second conductivity type are opposite.

[0047] Step S4: A first electrode 5 is prepared on the second side of an inorganic semiconductor substrate 1 of the first conductivity type, and a second electrode 6 is prepared on the first side of an organic semiconductor layer 4 of the second conductivity type; the first side and the second side are opposite sides.

[0048] like Figure 3As shown, in some embodiments, an organic semiconductor layer 4 of a second conductivity type is formed on an inorganic semiconductor epitaxial layer 3 with a second doping concentration, including: depositing organic small molecules or diketopyrrolopyrrolo-thiophenolothiophene copolymers with a molecular weight of less than 2000 g / mol as the organic semiconductor layer 4 of the second conductivity type on the inorganic semiconductor epitaxial layer 3 with a second doping concentration by organic molecular beam evaporation.

[0049] It is worth noting that the present invention can also achieve the same function using various other processes and material combinations. For example, solution processing methods, such as spin coating or blade coating, can be used to coat the surface of the epitaxial layer with a chloroform or toluene solution of decyl-substituted dinaphthothiophene, followed by annealing to form a uniform organic layer of the second conductivity type, suitable for low-cost, large-area flexible device manufacturing. Inkjet printing technology can also be used to precisely pattern and deposit ink containing pentaphenyl, achieving high-resolution device integration. In scenarios where high film purity and interface control are required, high-vacuum thermal evaporation can also be used to deposit small-molecule organic semiconductors to ensure excellent electrical performance.

[0050] like Figure 4 As shown, in some embodiments, a second electrode 6 is prepared on the first side of an organic semiconductor layer 4 of a second conductivity type, including sputtering at least one of gold and titanium as the second electrode 6 on the organic semiconductor layer 4 of the second conductivity type by physical vapor deposition.

[0051] In some specific embodiments, a first electrode 5 is fabricated on the back side of an inorganic semiconductor substrate 1 of the first conductivity type, and a second electrode 6 is fabricated on the first side of an organic semiconductor layer 4 of the second conductivity type. The first electrode 5 is used to form a low-resistance ohmic contact with the substrate of the first conductivity type. It can be formed by sequentially depositing titanium and gold on the second side of the substrate using physical vapor deposition (PVD) or electron beam evaporation processes, creating a titanium-gold stacked structure, for example, a 20nm titanium layer and a 100nm gold layer. The titanium layer facilitates good interfacial reaction and adhesion with the wide bandgap semiconductor of the first conductivity type, while the gold layer provides high conductivity and environmental stability.

[0052] Accordingly, the second electrode 6, acting as the anode, needs to achieve efficient hole collection with the organic semiconductor of the second conductivity type. High work function materials are typically selected, such as gold deposited by thermal evaporation with a thickness ranging from 50 to 100 nm. In specific flexible applications, sputtered titanium can also be used as the second electrode 6. Although its work function is lower, acceptable hole injection efficiency can be achieved by controlling the interface barrier through plasma treatment or the introduction of self-assembled monolayers (SAMs). This satisfies the requirements for efficient carrier injection and extraction while being compatible with flexible substrate processing and large-scale manufacturing processes, thereby ensuring that the comprehensive performance advantages of the organic diode in this embodiment in terms of high withstand voltage, low leakage current, and high rectification ratio are fully utilized.

[0053] A third embodiment of the present invention provides a performance testing method for organic diodes, comprising: using a Keithley 4200-SCS semiconductor parameter analyzer, in conjunction with a probe station, to measure current-voltage (IV) characteristics. Wherein, as Figure 5 The test range shown is −20V to +20V, with a voltage step size of 0.1V and an integration time of 100ms for each data point to ensure stable readings and accurate capture of rectification behavior under low bias. Figure 6 As shown, due to equipment power limitations, only reverse bias voltage testing was performed, with a scan range of −600V to 0V, a step size of 10V, and an integration time extended to 500ms to improve the detection accuracy of weak reverse leakage current. Electrode contact was achieved using tungsten probes on the probe station, ensuring good electrical connection while avoiding mechanical damage to the organic thin film. All tests were based on nine structurally identical independent diodes fabricated on the same SiC wafer, with each diode's position clearly marked to assess process uniformity and device consistency. To improve data reliability, each device underwent at least three complete IV scans, and the final result was averaged to reduce random errors. Furthermore, the raw current data were normalized to current density (unit: A / cm²) based on the effective device area, thereby eliminating the influence of size differences and ensuring comparability of electrical performance between different devices.

[0054] In some embodiments, such as Figure 5 The figure shows the current density-voltage (CDV) characteristics of the device over a voltage range of ±20V. It includes test results from nine independent diode devices fabricated on the same silicon carbide substrate of the first conductivity type. All curves highly overlap, indicating good uniformity and process repeatability. Under forward bias, the device conducts rapidly, and the current density increases exponentially with voltage. Under reverse bias, leakage current is effectively suppressed, with the current density below 10⁻⁻⁶ at −20V. 9 A / cm². Based on this, the device achieves a rectification ratio of approximately 1.7 × 10⁻⁶ at a bias of ±20V. 7 It is significantly superior to traditional organic diodes.

[0055] To further verify its pressure resistance, such as Figure 6 The figure shows the current density-voltage characteristics of nine devices from the same batch under high reverse bias, with a test voltage range of 0 to −600V. The results show that even under the extreme reverse bias of −600V, the leakage current of all devices remains stably maintained at 10⁻⁻⁶. 8The results, measured in the A / cm² range, showed no breakdown inflection point or sudden current surge, indicating that the device possesses excellent high-voltage blocking capability. Although the two sets of tests were conducted separately due to equipment power limitations, they were both based on devices fabricated using the same wafer, structure, and process, resulting in highly consistent and complementary data.

[0056] In summary, this invention successfully achieves a balance between high voltage withstand capability, ultra-low reverse leakage current, and high rectification ratio through the synergistic design of an epitaxial layer with a second doping concentration and a wide bandgap inorganic substrate, fully meeting the application requirements of flexible high-voltage electronics and high-reliability optoelectronic devices.

[0057] The organic / inorganic heterojunction diode provided by this invention can be widely used in various cutting-edge electronic and optoelectronic fields. In flexible displays, this device can serve as a rectifier unit or protection diode in pixel driving circuits, utilizing its high rectification ratio and mechanical flexibility to improve the stability and lifespan of the display screen under bending conditions. In solid-state lighting systems, it can be used as a bridge rectifier module for AC-driven LEDs, reducing energy loss and improving luminous efficiency due to its low leakage current and high withstand voltage characteristics. In the field of biosensing, its ultra-low reverse leakage current and high signal-to-noise ratio make it suitable for detecting weak photocurrents, such as for signal readout circuits in wearable photoplethysmography (PPG) sensors or fluorescent biological probes. In energy harvesting, this diode can be integrated into flexible photovoltaic or thermoelectric energy harvesting systems as a key component for efficient AC-DC conversion or blocking reverse current, preventing energy backflow from the energy storage unit. Furthermore, the heterojunction structure formed by the inorganic epitaxial layer with the second doping concentration and the organic semiconductor with the second conductivity type can be further extended to transistors, such as the base-emitter junction of a vertical heterojunction transistor. By utilizing its steep band gradient and low interface defect density, it can achieve high current gain and fast switching characteristics, providing basic device support for high-performance hybrid organic-inorganic integrated circuits.

[0058] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.

[0059] The above description of the embodiments is intended to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope and spirit of the invention are within the scope of the present invention.

Claims

1. An organic diode, characterized in that, include: Inorganic semiconductor substrate of the first conductivity type; At least two layers of epitaxial structure of a first conductivity type, wherein the at least two layers of epitaxial structure of the first conductivity type are located on a first side of an inorganic semiconductor substrate of the first conductivity type; The at least two-layer epitaxial structure of the first conductivity type includes: an inorganic semiconductor epitaxial layer with a first doping concentration located on a first side of an inorganic semiconductor substrate of the first conductivity type, and an inorganic semiconductor epitaxial layer with a second doping concentration located above the inorganic semiconductor epitaxial layer with the first doping concentration; the first doping concentration is higher than the second doping concentration. An organic semiconductor layer of the second conductivity type is located on an inorganic semiconductor epitaxial layer of the second doping concentration; the first conductivity type and the second conductivity type are opposite. A first electrode is located on the second side of an inorganic semiconductor substrate of the first conductivity type; The second electrode is located on the first side of the organic semiconductor layer of the second conductivity type; the first side and the second side are opposite sides.

2. The organic diode according to claim 1, characterized in that, The inorganic semiconductor substrate of the first conductivity type has a band gap greater than 2.3 eV.

3. The organic diode according to claim 2, characterized in that, The inorganic semiconductor substrate of the first conductivity type is made of at least one of silicon carbide, gallium nitride, gallium oxide, and aluminum nitride.

4. The organic diode according to claim 1, characterized in that, The organic semiconductor layer of the second type of conductivity is made of small organic molecules with a molecular weight of less than 2000 g / mol or diketopyrrolopyrrolo-thiophenothiophene copolymer.

5. The organic diode according to claim 4, characterized in that, The organic small molecule includes at least one of 2,7-dioctylbenzothiophene, decyl-substituted dinaphthothiophene, and pentabenzene.

6. The organic diode according to claim 1, characterized in that, The thickness of the inorganic semiconductor epitaxial layer with the second doping concentration ranges from 1 μm to 1000 μm.

7. The organic diode according to claim 1, characterized in that, The first electrode and the second electrode are made of at least one of gold and titanium.

8. The organic diode according to claim 1, characterized in that, The at least two-layer epitaxial structure of the first conductivity type further includes: at least one transition epitaxial layer located between the inorganic semiconductor epitaxial layer with the first doping concentration and the inorganic semiconductor epitaxial layer with the second doping concentration, wherein the doping concentration of the transition epitaxial layer is lower than the first doping concentration and higher than the second doping concentration.

9. A method for manufacturing an organic diode, characterized in that, include: Provide an inorganic semiconductor substrate of the first conductivity type; An inorganic semiconductor epitaxial layer with a first doping concentration and an inorganic semiconductor epitaxial layer with a second doping concentration are sequentially grown on the first side of an inorganic semiconductor substrate of the first conductivity type; the first doping concentration is higher than the second doping concentration. An organic semiconductor layer of a second conductivity type is formed on an inorganic semiconductor epitaxial layer with the second doping concentration; the first conductivity type and the second conductivity type are opposite. A first electrode is formed on the second side of an inorganic semiconductor substrate of the first conductivity type, and a second electrode is formed on the first side of an organic semiconductor layer of the second conductivity type; the first side and the second side are opposite sides.

10. The manufacturing method according to claim 9, characterized in that, Forming an organic semiconductor layer of a second conductivity type on an inorganic semiconductor epitaxial layer of the second doping concentration includes: depositing organic small molecules or diketopyrrolopyrrolo-thiophenothiophene copolymers with a molecular weight of less than 2000 g / mol on the inorganic semiconductor epitaxial layer of the second doping concentration as an organic semiconductor layer of the second conductivity type by organic molecular beam evaporation.

11. The manufacturing method according to claim 9, characterized in that, The preparation of a second electrode on a first side of an organic semiconductor layer of the second conductivity type includes: sputtering at least one of gold and titanium as a second electrode on the organic semiconductor layer of the second conductivity type by physical vapor deposition.

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