A novel nanorod-based electrically pumped laser device

Abstract

The application discloses a novel nanorod-based electrically pumped laser device. The device comprises a conductive substrate, a hole transport layer, a nanorod light-emitting layer, an electron transport layer and a cathode electrode layer which are sequentially stacked, the hole transport layer and the cathode electrode layer are both in a strip pattern, the strip pattern directions of the hole transport layer and the cathode electrode layer are orthogonal, the nanorod light-emitting layer is composed of horizontally oriented randomly distributed nanorods, the end surface of the nanorod is flat and can form a self-constructed resonant cavity, and the gaps between the hole transport layers and between the hole transport layer and the electron transport layer are filled with an insulating filling layer. The orthogonalization pattern processing of the hole transport layer and the cathode electrode layer greatly increases the number of micro-nano lasers in the single device preparation process, so that a large number of randomly distributed nanorods can form effective lasers, the device yield can be effectively improved, and the cost can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser technology, in particular to a novel electrically pumped laser device based on nanorods. BACKGROUND

[0002] With the development of micro-nano technology and micro-nano photonics, micro-nano laser has attracted much attention. Micro-nano laser is a micro-nano device using micro / nano rods and other luminescent materials as resonant cavity, which emits laser under optical pumping or electrical pumping. Due to the fact that the size of the resonant cavity in the micro-nano laser is comparable to the wavelength of the emitted light, some unique physical effects will occur in the electromagnetic resonant cavity, which is of great significance for basic research. At the same time, micro-nano laser has wide application prospects in the fields of optical computing, information storage and nano analysis.

[0003] However, the preparation process of micro-nano laser is strict, requiring ultra-fine micro-nano processing technology, and at the same time, the preparation of micro-nano materials such as nanorods has high requirements, such as strict growth orientation, arrangement mode, size, etc. These challenges for the preparation process of micro-nano laser hinder the development of new micro-nano laser and the advancement of related basic research, and also increase the production cost. SUMMARY

[0004] In view of the above shortcomings of the prior art, the purpose of the present application is to provide a novel electrically pumped laser device based on nanorods. By using nanorods with self-constructed resonant cavity, and orthogonal patterning of the hole transport layer and the cathode electrode layer, electrically pumped laser emission of horizontally oriented nanorods can be obtained. At the same time, the present application greatly reduces the requirements of micro-nano processing technology for realizing micro-nano laser, which can save cost.

[0005] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0006] A novel electrically pumped laser device based on nanorods, comprising a conductive substrate, a hole transport layer, a nanorod luminescent layer, an electron transport layer, and a cathode electrode layer which are sequentially stacked, the hole transport layer and the cathode electrode layer are both in strip-shaped pattern, and the strip-shaped pattern directions of the hole transport layer and the cathode electrode layer are orthogonal, the nanorod luminescent layer is composed of horizontally oriented and randomly distributed nanorods, and the end face of the nanorod is flat and can self-construct a resonant cavity, and the gaps between the hole transport layers and between the hole transport layer and the electron transport layer are filled with an insulating filling layer.

[0007] In the above technical scheme, further, the thickness of the hole transport layer is 10-150 nm; the material of the hole transport layer can be, but is not limited to, at least one of p-type Si, p-type GaN, PEDOT:PSS, TFB, poly-TPD, PVK, NiO, and Mo03.

[0008] Further, the material of the nanorod luminescent layer can be, but is not limited to, CdSe, CdZnS, ZnS, Cd x Zn 1- x Se y S 1-y one of the group 2-6 core-shell semiconductor materials, group 4-6 semiconductor materials such as PbSe, PbS, perovskite luminescent materials such as MAPbX3, FAPbX3, CsPbX3, and group 1-3-6 semiconductor materials such as Cu-In-S.

[0009] Further, the thickness of the electron transport layer is 10-150 nm; the material of the electron transport layer can be, but is not limited to, one of ZnO, Alq3, TPBi, and PO-T2T.

[0010] Further, the material of the insulating filling layer can be, but is not limited to, one of Al2O3, LiF, and PMMA.

[0011] Further, the material of the conductive substrate can be, but is not limited to, one of Si, GaN, ITO glass, and FTO glass.

[0012] Further, the material of the cathode electrode layer can be, but is not limited to, one of LiF / Al electrode, Ag electrode, and Ti / Au electrode, and the thickness of the cathode electrode layer is 100-200 nm.

[0013] The manufacturing method of the novel nanorod-based electroluminescent device comprises the following steps:

[0014] forming a hole transport layer with a strip-shaped pattern on a conductive substrate, then forming a nanorod luminescent layer on the hole transport layer, then filling an insulating filling layer into the internal voids of the hole transport layer and the nanorod luminescent layer, forming an electron transport layer on the nanorod luminescent layer, and then forming a cathode electrode layer with a strip-shaped pattern on the electron transport layer, wherein the strip-shaped pattern of the cathode electrode layer is orthogonal to the direction of the strip-shaped pattern of the hole transport layer.

[0015] Further, the hole transport layer can be directly in-situ etched on the conductive substrate, or can be obtained by redeposition or growth on the conductive substrate, or can be obtained by etching after deposition or growth on the conductive substrate.

[0016] Further, the nanorod luminescent layer is obtained by in-situ growth or by transfer or dispersion.

[0017] Further, the insulating filling layer can be prepared by spin coating or deposition, but should not completely cover the nanorod light emitting layer, so that the nanorod light emitting layer is in contact with the electron transport layer.

[0018] Further, the insulating filling layer is subjected to plasma treatment after preparation, so that the surface of the nanorod light emitting layer is exposed.

[0019] The present application has the following advantages:

[0020] The novel nanorod-based electroluminescent device provided by the present application comprises, in sequence, a conductive substrate, a hole transport layer, a nanorod light emitting layer, an electron transport layer, and a cathode electrode layer, and further comprises an insulating filling layer. The orthogonalization pattern processing of the hole transport layer and the cathode electrode layer greatly increases the number of effective micro / nano lasers in the device. For example, if the strip pattern of the hole transport layer and the cathode electrode layer is 100 strips, the device can have up to 100x100 micro / nano lasers, which can effectively improve the yield of the laser device. Meanwhile, the preparation process cost of the device is lower than that of the conventional nanorod laser device. In the conventional nanorod laser device preparation process, a strict micro / nano processing process is required to ensure the directional growth of the nanorod and the flatness of the end face to form a self-resonant cavity. Meanwhile, a high-precision micro / nano process is used to ensure the strict alignment of the hole transport layer and the electron transport layer with the nanorod, which has a high production cost. In the novel nanorod-based electroluminescent device provided by the present application, the orthogonalization pattern processing of the hole transport layer and the cathode electrode layer greatly increases the number of micro / nano lasers in the single device preparation process, so as to ensure that a large number of randomly distributed nanorods form effective lasers. That is, in addition to the nanorods with unreasonable positions and uneven end faces, there are still many nanorods with reasonable positions and flat end faces that can form self-resonant cavities, thereby improving the yield of the device and reducing the cost. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 FIG. 1 is a structural schematic diagram of the novel nanorod-based electroluminescent device according to the present application.

[0022] Figure 2 FIG. 2 is a pattern schematic diagram of the hole transport layer in the novel nanorod-based electroluminescent device according to the present application.

[0023] Figure 3 FIG. 3 is a distribution schematic diagram of the nanorod light emitting layer in the novel nanorod-based electroluminescent device according to the present application.

[0024] Figure 4 FIG. 4 is a pattern schematic diagram of the cathode electrode layer in the novel nanorod-based electroluminescent device according to the present application. DETAILED DESCRIPTION

[0025] The present application aims to provide a novel nanorod-based electrically pumped laser device. To make the purpose, technical solutions and effects of the present application clearer and more explicit, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0026] Referring to Figure 1 The present application provides a novel nanorod-based electrically pumped laser device, which comprises a conductive substrate 1, a hole transport layer 2, a nanorod light-emitting layer 4, an electron transport layer 5, and a cathode electrode layer 6, which are sequentially stacked, and further comprises an insulating filling layer 3 filled in the gaps between the hole transport layer and the electron transport layer. The nanorod light-emitting layer 4 is composed of horizontally oriented randomly distributed nanorods, and the end face of the nanorod is flat, which can form a resonant cavity, as shown in Figure 3 By applying a bias to the device, charges are injected into the nanorods to produce light emission and optical resonance, and then laser light is emitted from the end face of the nanorod. Finally, the laser light is emitted from the side of the device.

[0027] Further, in the novel nanorod-based electrically pumped laser device, the hole transport layer 2 is located on the conductive substrate 1, the nanorod light-emitting layer 4 is located on the hole transport layer 2, the insulating filling layer 3 fills the gaps inside the hole transport layer 2 and the electron transport layer 4, preventing the electron transport layer 5 from directly contacting the hole transport layer 2, which can cause short circuit of the device, the electron transport layer 5 is located on the nanorod light-emitting layer 4, and the cathode electrode layer 6 is located on the electron transport layer 5.

[0028] Further, in the novel nanorod-based electrically pumped laser device, to achieve effective injection of charges into the horizontally oriented randomly distributed single nanorods, a patterned hole transport layer 2 and a cathode electrode layer 6 are used, referring to Figure 2 and Figure 4 The hole transport layer 2 and the cathode electrode layer 6 are prepared in the shape of a strip pattern, and the strip patterns of the hole transport layer 2 and the cathode electrode layer 6 are orthogonal in the horizontal direction.

[0029] Further, the manufacturing method of the novel nanorod-based electrically pumped laser device comprises the following steps: first, providing a conductive substrate 1. Then, forming a hole transport layer 2 with a strip pattern on the conductive substrate 1, and then forming a nanorod light-emitting layer 4 on the hole transport layer 2. Next, filling an insulating filling layer 3 into the internal gaps of the hole transport layer 2 and the nanorod light-emitting layer 4. Next, forming an electron transport layer 5 on the nanorod light-emitting layer 4, and then forming a cathode electrode layer 6 with a strip pattern on the electron transport layer 5, wherein the strip pattern of the cathode electrode layer 6 is orthogonal to the strip pattern of the hole transport layer 2 in the horizontal direction.

[0030] Further, in practical applications, the material of the electric substrate 1 can be, but is not limited to, one of Si, GaN, ITO glass, FTO glass. The material of the hole transport layer 2 can be, but is not limited to, at least one of p-type Si, p-type GaN, PEDOT:PSS, TFB, poly-TPD, PVK, NiO, MoO3, and the thickness of the hole transport layer is 10-150 nm. The material of the insulating filling layer 3 can be, but is not limited to, one of Al2O3, LiF, PMMA. The material of the nanorod light-emitting layer 4 can be, but is not limited to, one of CdSe, CdZnS, ZnS, Cd x Zn 1-x Se y S 1-y 2-6 group core-shell semiconductor materials, 4-6 group semiconductor materials such as PbSe and PbS, perovskite light-emitting materials such as MAPbX3, FAPbX3, and CsPbX3, and 1-3-6 group semiconductor materials such as Cu-In-S. The material of the electron transport layer 5 can be, but is not limited to, one of ZnO, Alq3, TPBi, and PO-T2T, and the thickness of the electron transport layer is 10-150 nm. The material of the cathode electrode layer 6 can be, but is not limited to, one of LiF / Al electrode, Ag electrode, and Ti / Au electrode, and the thickness of the cathode electrode layer is 100-200 nm.

[0031] The novel nanorod-based electric laser device according to the present application is described in detail below in combination with the accompanying drawings and examples.

[0032] Example 1

[0033] A 40-nm p-type GaN layer is epitaxially grown on a GaN substrate as a hole transport layer, and the p-type GaN layer is made into a strip pattern by photolithography. A nanorod with a horizontal orientation and a flat end surface is grown on the p-type GaN layer by CVD as a resonant cavity for laser emission. PMMA is spin-coated on the nanorod light-emitting layer as an insulating filling layer, and the PMMA covering the upper part of the nanorod is removed by plasma treatment to make the nanorod light-emitting layer in good contact with a subsequently deposited electron transport layer. The electron transport layer is obtained by spin-coating a ZnO colloidal solution, and the thickness is 30 nm. Finally, a LiF / Al electrode with a thickness of 1 nm / 100 nm is evaporated as a cathode to obtain a nanorod electric laser device.

[0034] Example 2

[0035] The p-type heavily doped Si is used as the conductive substrate and the hole transport layer, and the p-type region of the Si surface layer is made into a strip pattern by photolithography, the etching depth of the p-type Si is 40 nm, then the horizontal orientation random distribution and flat end surface nanorods are in-situ grown on the p-type Si by liquid phase growth method as the resonant cavity for laser emission, 45 nm Al2O3 is deposited on the nanorod luminescent layer by ALD as the insulating filling layer to ensure that the side surface area of the nanorod is exposed to be in good contact with the subsequently deposited electron transport layer. The electron transport layer is obtained by thermal evaporation deposition, and the thickness is 40 nm of TPBi. Finally, the Ti / Au electrode with a thickness of 35 nm / 100 nm is evaporated as the cathode to obtain the nanorod electroluminescent device.

[0036] Example 3

[0037] The ITO with a thickness of 120 nm is deposited on a glass substrate as the conductive substrate, and the ITO is made into a strip pattern by photolithography, the etching depth is 40 nm, the PEDOT:PSS / TFB with a thickness of 40 nm / 20 nm is deposited on the ITO as the hole transport layer, the horizontal orientation random distribution and flat end surface nanorods are deposited on the TFB by dry transfer as the resonant cavity for laser emission, the PMMA is spin-coated on the nanorod luminescent layer as the insulating filling layer, and the PMMA covering the upper part of the nanorod is removed by plasma treatment to make the nanorod luminescent layer in good contact with the subsequently deposited electron transport layer. The electron transport layer is obtained by spin-coating the ZnO colloidal solution, and the thickness is 30 nm. Finally, the LiF / Al electrode with a thickness of 1 nm / 100 nm is evaporated as the cathode to obtain the nanorod electroluminescent device.

[0038] In summary, the novel nanorod-based electroluminescent device provided by the application comprises a conductive substrate, a hole transport layer, a nanorod luminescent layer, an electron transport layer, a cathode electrode layer which are sequentially arranged in layers, and an insulating filling layer arranged between the electron transport layer and the hole transport layer. The nanorod luminescent layer requires that the nanorods used have flat end surfaces and can self-construct a resonant cavity. The novel nanorod-based electroluminescent device provided by the application utilizes the self-constructed resonant cavity of the nanorods, and the patterning of the hole transport layer and the cathode electrode layer, so that the horizontal orientation random distribution of the nanorods can be realized, the preparation process of the nanorod laser is simplified, and the cost is saved.

[0039] It should be understood that the application of the application is not limited to the above examples, and those skilled in the art can make improvements or changes according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the application.

Claims

1. A novel electro-laser device based on nanorods, characterized in that, The device comprises a conductive substrate, a hole transport layer, a nanorod luminescent layer, an electron transport layer, and a cathode electrode layer stacked sequentially. The hole transport layer and the cathode electrode layer are both strip-shaped patterns, and the strip-shaped patterns of the hole transport layer and the cathode electrode layer are orthogonal. The nanorod luminescent layer is composed of horizontally oriented, randomly distributed nanorods, and the end faces of the nanorods are flat and can form a resonant cavity. The gaps between the hole transport layers and between the hole transport layer and the electron transport layer are filled with an insulating filler layer.

2. A method for manufacturing the novel nanorod-based electro-laser device as described in claim 1, characterized in that, Includes the following steps: A hole transport layer (2) with a striped pattern is formed on a conductive substrate (1). Then, a nanorod light-emitting layer (4) is formed on the hole transport layer (2). Next, an insulating filling layer (3) is filled into the gap between the hole transport layer (2) and the nanorod light-emitting layer (4). An electron transport layer (5) is formed on the nanorod light-emitting layer (4). Then, a cathode electrode layer (6) with a striped pattern is formed on the electron transport layer (5), wherein the striped pattern of the cathode electrode layer (6) is orthogonal to the striped pattern of the hole transport layer (2).

3. The method for manufacturing the novel electro-laser device based on nanorods as described in claim 2, characterized in that, The hole transport layer can be obtained by directly etching the conductive substrate in situ, or by redeposition or growth on the conductive substrate, or by first depositing or growing on the conductive substrate and then etching.

4. The method for manufacturing the novel electro-laser device based on nanorods as described in claim 2, characterized in that, The nanorod luminescent layer is obtained by in-situ growth or by transfer or dispersion.

5. The method for manufacturing the novel electro-laser device based on nanorods as described in claim 2, characterized in that, The insulating filling layer is prepared by spin coating or deposition, but it should not completely cover the nanorod luminescent layer so that the nanorod luminescent layer remains in contact with the electron transport layer.

6. The method for manufacturing the novel electro-laser device based on nanorods as described in claim 5, characterized in that, After preparing the insulating filling layer, the prepared insulating filling layer is subjected to plasma treatment to expose the surface of the nanorod luminescent layer.

7. The device as described in claim 1 or the method according to any one of claims 2-6, characterized in that, The hole transport layer has a thickness of 10-150 nm; the electron transport layer has a thickness of 10-150 nm; and the cathode electrode layer has a thickness of 100-200 nm.

8. The device as claimed in claim 1 or the method of any one of claims 2-6, characterized in that, The hole transport layer is made of at least one of p-type Si, p-type GaN, PEDOT:PSS, TFB, poly-TPD, PVK, NiO, and MoO3. The nanorod luminescent layer is made of one of group 2-6 core-shell semiconductor materials, group 4-6 semiconductor materials, perovskite luminescent materials, and group 1-3-6 semiconductor materials. The electron transport layer is made of one of ZnO, Alq3, TPBi, and PO-T2T.

9. The device as claimed in claim 1 or the method of any one of claims 2-6, characterized in that, The material of the insulating filler layer is selected from Al2O3, LiF, and PMMA.

10. The device as claimed in claim 1 or the method of any one of claims 2-6, characterized in that, The conductive substrate is made of one of Si, GaN, ITO glass, and FTO glass, and the cathode electrode layer is made of one of LiF / Al electrode, Ag electrode, and Ti / Au electrode.

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