CN101060166A - An optically transparent electrode and its manufacture method - Google Patents

Abstract

The disclosed transparent electrode comprises a substrate and a multicrystal silicon layer on the substrate, wherein the multicrystal silicon film can be made of amorphous silicon, monocrystal silicon, or other silicon compound. The preparation method can be low-cost magnetron sputtering or electron beam evaporation, just needs the vacuum degree up to 10-5Pa. compared with IPO film, this invention reduces cost, and improves product performance well.

Description

A light-transmitting electrode and its preparation method

technical field

The invention relates to a light-transmitting electrode and a preparation method thereof.

Background technique

At present, the common organic electroluminescent devices are based on transparent conductive glass, and the light is emitted from the bottom; but in some applications, the light must be emitted from the top. Even in some cases where ITO is used as the anode, light is required to exit from the top. The organic light-emitting diodes that emit light have opened up a new field of research on organic light-emitting devices and broader application prospects. For example, when using silicon wafers as substrates, the driving circuits of organic light-emitting devices can be prepared on Si in advance, and then organic light-emitting devices can be fabricated. layer, and finally prepare the top-out photoelectrode, thus realizing silicon-based optoelectronic integration. The resolution, refresh rate and power consumption of silicon-based organic display devices are generally superior to existing ITO-based organic light-emitting devices. In photoelectric conversion, such as solar cells and photodiodes, light-transmitting electrodes are also required.

For light-transmitting electrodes, there are many materials to choose from, but ultimately a balance must be struck between light transmittance and conductivity. In terms of organic luminescence, ITO and thin Al/Ag or LiF/Al/Ag composite layers (Al is usually on the order of nm) are mostly used at present, and are mostly used as cathodes. However, the former has high requirements for equipment and processes because the deposition of ITO is easy to damage the organic light-emitting layer; while the latter leads to low quantum efficiency in the device, severe reflection, low light transmittance, and poor stability.

Contents of the invention

The object of the present invention is to provide a light-transmitting electrode with adjustable work function, small interface reflection, high light transmittance and good chemical stability and a preparation method thereof.

The light-transmitting electrode provided by the present invention includes a transparent substrate and a polysilicon layer on the transparent substrate.

In order to improve the stability and electrical contact performance of the electrode, the polysilicon film should be more than 10nm in thickness. In order to ensure a high light transmittance, the thickness should be below 100nm. If it is used in the infrared band, the thickness can be increased to the order of microns.

During use, any graphic template can be added to the above-mentioned top electrode as required.

The electrode can be prepared by the following two methods:

The first is to deposit a polysilicon layer directly on the substrate;

Here, the direct deposition of the polysilicon layer may first deposit an amorphous silicon layer on the substrate, and then anneal the amorphous silicon layer at 900-1100°C to form a polysilicon layer; or, while depositing the amorphous silicon layer, anneal at 900-1100 and heating at ℃ to anneal the amorphous silicon layer deposited on the substrate to form a polysilicon layer to obtain the light-transmitting electrode.

Here, deposition can be done by magnetron sputtering evaporation, electron beam evaporation, ion beam evaporation, molecular epitaxy evaporation or vapor phase chemical deposition.

The second is to deposit an amorphous silicon layer on a transparent substrate, then deposit a Ni layer or an Al layer on the amorphous silicon layer, then anneal at 450-650°C for 20min-48h to form a polysilicon layer, and finally wash off the Ni layer or Al layer to obtain the light-transmitting electrode.

Here, deposition can also be done by magnetron sputtering evaporation, electron beam evaporation, ion beam evaporation, molecular epitaxy evaporation or vapor phase chemical deposition.

The thickness of the amorphous silicon layer is 10-100 nm; the thickness of the Ni layer or Al layer is 1-10 nm. Cleaning can use hydrochloric acid or nitric acid solution.

The invention uses the polysilicon thin film as the light-transmitting electrode, which can take into account basic elements such as light transmittance, stability and low cost. The raw material can be amorphous silicon, single crystal silicon tailings, or other silicon compounds; the preparation process can be low-cost magnetron sputtering or electron beam evaporation, etc., and the vacuum can be above 10 ^-5 Torr. Compared with thin metal light-transmitting electrodes, the light transmittance is high and stable. Compared with ITO thin films, the material and process costs are lower. The light-transmitting electrode of the invention is also widely used in inorganic thin films, organic thin films and semiconductor luminescence, as well as photoelectric devices and photodetectors.

Detailed ways

Embodiment 1, prepare polysilicon thin film with magnetron sputtering on glass pad

A 25nm amorphous silicon film was deposited on a glass substrate with a magnetron sputtering device, and then 2nm Ni was deposited. It is required that the vacuum degree is above 10 ^-5 Torr, the material purity is above 99.99%, and the silicon target material used is single crystal silicon. The sample was taken out and annealed (crystallized) at 600° C. for 30 minutes under the protection of nitrogen, and then cleaned with dilute nitric acid to remove the Ni layer to obtain an electrode with a polysilicon film layer. After testing, the visible light transmittance of the electrode is 60%, the infrared light transmittance is about 80%, and the conductivity is stable.

Embodiment 2, prepare polysilicon film with chemical vapor deposition

Using conventional plasma-enhanced chemical vapor deposition equipment, the substrate is glass, the reaction gas is silane, diluted with Ar gas, a 70nm amorphous silicon film is deposited on the substrate, and then annealed at 950°C for 120min in a vacuum to obtain a polycrystalline silicon film layer the electrodes. After testing, the visible light transmittance of the electrode is 40%, the infrared light transmittance is about 60%, and the conductivity is stable.

Embodiment 3, direct deposition prepares polysilicon layer

Use magnetron sputtering equipment to deposit on a quartz substrate. While depositing, the substrate is heated in situ to 1050°C, the vacuum degree is above 10 ^-5 Torr, and the purity of the silicon single crystal target material is above 99.99%. On the quartz substrate Deposit a polysilicon film layer with a thickness of 25 mm on it to obtain an electrode with a polysilicon film layer. After testing, the visible light transmittance of the electrode is 60%, the infrared light transmittance is about 80%, and the conductivity is stable.

Embodiment 4,

A 50nm amorphous silicon film was deposited on a glass substrate with a magnetron sputtering device, and then 8nm Al was deposited. It is required that the vacuum degree is above 10 ^-5 Torr, the material purity is above 99.99%, and the silicon target material used is single crystal silicon. The sample was taken out and annealed (crystallized) at 500° C. for 1 hour under the protection of nitrogen, and then washed with dilute hydrochloric acid to remove the Al layer. At this time, the visible light transmittance is 50%, the infrared light transmittance is about 70%, and the conductivity is stable.

Claims (9)

1. A light-transmitting electrode, comprising a transparent substrate and a polysilicon layer on the transparent substrate. 2. The light-transmitting electrode according to claim 1, wherein the thickness of the polysilicon layer is 10-100 nm. 3. The preparation method of the light-transmitting electrode as claimed in claim 1, wherein a polysilicon layer is directly deposited on the transparent substrate. 4. The preparation method according to claim 3, characterized in that: the direct deposition of the polysilicon layer is to deposit an amorphous silicon layer on the substrate first, and then anneal the amorphous silicon layer at 900-1100°C to form a polysilicon layer , to obtain the light-transmitting electrode. 5. The preparation method according to claim 3, characterized in that the direct deposition of the polysilicon layer is at the same time as depositing the amorphous silicon layer on the substrate, heating at 900-1100°C to make the amorphous silicon layer deposited on the substrate The silicon layer is annealed to form a polysilicon layer to obtain the light-transmitting electrode. 6. The preparation method according to claim 3, 4 or 5, characterized in that the thickness of the polysilicon layer is 10-100 nm. 7. The preparation method of the light-transmitting electrode according to claim 1 is to deposit an amorphous silicon layer on a transparent substrate, then deposit a Ni layer or an Al layer on the amorphous silicon layer, and then anneal at 450-650°C for 20min- 48h to form a polysilicon layer, and finally wash away the Ni layer or Al layer to obtain the light-transmitting electrode. 8. The preparation method according to claim 7, characterized in that: the thickness of the amorphous silicon layer is 10-100 nm; the thickness of the Ni layer or Al layer is 1-10 nm. 9. The preparation method according to claim 7, characterized in that hydrochloric acid or nitric acid solution is used for cleaning.