CN205960006U - Room temperature infrared detector based on graphite alkene nanometer wall / silicon - Google Patents

Abstract

The utility model discloses a room temperature infrared detector based on graphene nano-wall/silicon. In the wall electrode layer, there is at least one contact between the graphene nano-wall and the N-type silicon sheet layer, and the contact is the active area of the detector. The room temperature infrared detector based on graphene nano-wall/silicon disclosed by the utility model combines excellent properties such as high conductivity and low resistivity of graphene nano-wall, and the detector mainly utilizes graphene nano-wall layer to detect infrared light Absorption, the graphene nanowall layer can absorb ultraviolet-visible-near, middle and far-infrared light in a wide band at room temperature. After the graphene nanowall layer absorbs light in the near-middle-far infrared band, electron-hole pairs are generated , forming a space electric field region, thereby realizing the detection of infrared light by the infrared detector at room temperature.

Description

Room temperature infrared detector based on graphene nanowall/silicon

technical field

The utility model belongs to the field of photoelectric detectors, in particular to a room temperature infrared detector based on graphene nano-wall/silicon.

Background technique

The main principle of the photodetector is to convert the optical signal into an electrical signal. When there is light, the photo-excited hot carriers move from the top layer to the bottom layer, so that the charge gathers in the bottom layer to form a current. Photodetectors are widely used in various fields of military and national economy. Visible light or near-infrared bands are mainly used for ray measurement and detection, industrial automatic control, photometry, etc.; infrared radiation contains rich objective information, and it has attracted much attention for detection, mainly for missile manufacturing, infrared thermal imaging, and infrared remote sensing etc.

Graphene is a new material with a single-layer sheet structure composed of carbon atoms. It is a planar film composed of carbon atoms in a hexagonal honeycomb lattice with sp2 hybrid orbitals. It is a two-dimensional material with a thickness of only one carbon atom. . Because of its extremely low resistivity, extremely fast electron migration, and good transparency and thermal conductivity, it is expected to be used to develop a new generation of electronic components that are thinner and conduct electricity faster. Graphene nanowalls can also be called carbon walls and carbon nanosheets, which are criss-crossed graphene microsheets produced perpendicular to the substrate. As the growth time increases, the electrical conductivity and light absorption rate increase; at the same time, its highly open The boundary structure and abundant edge sites can effectively prevent the agglomeration of graphene sheets due to the interaction of π-π bonds. More defects provide more active sites, and the thickness is generally between several nanometers and tens of nanometers. Applying graphene nanowalls to the field of photodetectors will have greater advantages.

At present, the light absorption of graphene is small, resulting in a low response rate of graphene photodetectors, while the graphene nanowall increases the absorption of light, and at the same time, the heterojunction formed by the graphene nanowall and silicon is used for light generation. Therefore, using graphene nanowalls to develop new silicon-based heterojunction photodetectors can effectively detect infrared light at room temperature, which is a very promising technology.

Contents of the invention

In view of this, the purpose of this utility model is to provide a room temperature infrared detector based on graphene nanowall/silicon, which has the advantages of simple structure, convenient processing, strong light absorption capacity, high responsivity, fast response speed, etc. advantage.

In order to achieve the above object, the utility model specifically provides the following technical solutions:

1. A room-temperature infrared detector based on graphene nano-wall/silicon, comprising liquid gallium-indium alloy electrode layer, N-type silicon sheet layer, silicon dioxide layer, graphene nano-wall electrode layer from bottom to top, the graphite There is at least one contact between the ene nanowall and the N-type silicon layer, and the contact is the active area of the detector. The thickness of the N-type silicon layer is 10-500 μm, and the thickness of the silicon dioxide layer is 100-500 nm. The electrode layer thickness of the graphene nano wall is 100nm-10μm.

Preferably, the N-type silicon slice layer is an N-type lightly doped single crystal silicon slice.

Preferably, the cross-sectional area of the graphene nanowall electrode layer is smaller than that of the silicon dioxide layer.

Preferably, the infrared detector detects infrared light at room temperature, and the detection waveband is 1 μm-12 μm.

Preferably, it also includes a lower conductive substrate arranged on the lower part of the liquid gallium indium alloy electrode layer and an upper conductive substrate arranged on the upper part of the graphene nano-wall electrode layer.

Preferably, the lower conductive base is a base layer of copper tape, and the upper conductive base is an electrode layer of silver conductive glue.

Preferably, the upper conductive substrate is disposed outside the active area.

2. A method for preparing a room temperature infrared detector based on graphene nanowall/silicon, comprising the steps of:

S1: Choose an N-type silicon wafer with a silicon dioxide layer, etch the silicon dioxide so that there is at least one bare silicon area on the contact surface between the silicon dioxide layer and the N-type silicon wafer, and at the same time etch away the N-type silicon wafer. Silica produced on one side due to thermal oxidation;

S2: Clean the N-type silicon wafer treated in step S1 with acetone, alcohol, and deionized water in sequence, and then dry it with nitrogen;

S3: placing the N-type silicon wafer processed in step S2 in a plasma-enhanced chemical vapor deposition reaction chamber, feeding methane and hydrogen gas, and growing a graphene nano-wall electrode layer on the side with silicon dioxide;

S4: Brush the other side of the N-type silicon wafer with a graphene nanowall electrode layer on a layer of liquid gallium indium alloy electrode layer;

S5: attaching the N-type silicon chip treated in step S4 to the lower conductive substrate through the liquid gallium indium alloy electrode layer, and the lower conductive substrate is used as the lower surface electrode for external circuit testing;

S6: Coating an upper conductive substrate around the upper surface of the graphene nano-wall electrode layer outside the active area, and the upper conductive substrate is used as an upper surface electrode for external circuit testing.

Preferably, in step S3, the volume ratio of methane to hydrogen is 6:4, the growth temperature is 750° C., and the vacuum degree of the plasma-enhanced chemical vapor deposition reaction chamber is 50 Pa.

The basic principle of the utility model is: the silicon material can only absorb light with a wavelength less than 1.2 microns (that is, the near-infrared band just absorbs the cut-off), and the graphene nano-wall layer can resist ultraviolet-visible-near, middle and far infrared light at room temperature. Light is absorbed in a wide band; when the graphene nanowall layer absorbs light in the infrared band, electron-hole pairs are generated, and the electron-hole pairs are separated through the space electric field region formed between the graphene wall/silicon, In this way, the detection of infrared light by the infrared detector at room temperature is realized.

The beneficial effect of the utility model is that: the room temperature infrared detector based on graphene nano-wall/silicon disclosed by the utility model combines the excellent properties such as high conductivity and low resistivity of the graphene nano-wall, and the detector mainly utilizes graphite The graphene nanowall layer absorbs infrared light, and the graphene nanowall layer can absorb ultraviolet-visible-near, middle, and far infrared light in a wide band at room temperature. The graphene nanowall layer absorbs light in the near, middle, and far infrared bands Finally, electron-hole pairs are generated to form a space electric field region, thereby realizing the detection of infrared light by the infrared detector at room temperature. The photodetector has simple structure and convenient processing, and can be directly obtained by growing graphene nano-wall materials, which provides a direction for future industrialization development.

Description of drawings

In order to make the purpose, technical solutions and beneficial effects of the utility model clearer, the utility model provides the following drawings:

Fig. 1 is the schematic diagram of preparing graphene nano wall material based on PECVD method;

Fig. 2 is the structural representation of the room temperature infrared detector based on graphene nanowall/silicon;

Fig. 3 is the Raman spectrogram of graphene nano wall;

Figure 4 shows the measurement results of a room-temperature infrared detector based on graphene nanowall/silicon, and the test bands are mid- and far-infrared.

detailed description

Preferred embodiments of the present utility model will be described in detail below in conjunction with the accompanying drawings. For the experimental methods that do not specify specific conditions in the examples, usually follow the conventional conditions or the conditions suggested by the manufacturer.

The room temperature infrared detector based on graphene nanowall/silicon is prepared as follows:

S1: Select an N-type silicon wafer layer with a resistivity of 2-4Ω cm, a crystal orientation <100>, and a thickness of 525 μm, with a silicon dioxide layer with a thickness of 300 nm on the surface;

S2: Etch the silicon dioxide on the front side with hydrofluoric acid to expose the bare silicon area of 3mm*3mm as the active area of the photodetector, and at the same time etch the silicon dioxide layer on the back side of the N silicon layer due to thermal oxidation;

S3: ultrasonically clean the N-type silicon wafer layer in acetone for 10-15 minutes, then ultrasonically clean it in alcohol for 10-15 minutes, then ultrasonically clean it in pure water for 10-15 minutes, and finally dry it with nitrogen;

S4: Put the N-type silicon wafer layer in the plasma-enhanced chemical vapor deposition reaction chamber (PECVD), first use a mechanical pump to pump the pressure in the reaction chamber below 3Pa, then inject hydrogen gas, and turn off the hydrogen gas after the gas flow and pressure are stable , and then wait for the mechanical pump to pump the pressure of the reaction chamber below 3Pa, repeat this process 3 times to remove the impurity gas in the chamber; then turn on the hydrogen gas to raise the temperature to 750°C, adjust the hydrogen flow rate to 4 sccm, inject methane gas 6 sccm and turn on the radio frequency plasma Volume enhancement source, its power is set to 200W, air pressure is maintained at 50Pa, makes graphene nano wall electrode layer grow 20min-50min (interval of 10min, totally 4 samples);

S5: Brush the back of the N-type silicon sheet layer with the graphene nanowall electrode layer on a layer of liquid gallium-indium alloy electrode layer to form an ohmic contact with it;

S6: the infrared detector of graphene nano wall/silicon is attached on the base layer of copper tape through liquid gallium indium alloy electrode layer, and copper tape is used as the lower surface electrode of external circuit test;

S7: Evenly coat a layer of silver conductive adhesive layer around the electrode layer of the graphene nano-wall outside the active area, and use a silver wire to lead out as an upper surface electrode for external circuit testing.

Fig. 1 is the schematic diagram of preparing graphene nano wall material based on PECVD method, wherein, 1 is PECVD tubular furnace heating system; 2 is radio frequency plasma enhanced source; 3 is the temperature control chamber of PECVD tubular furnace; 4 is N 5 is the silicon dioxide layer; 6 is the graphene nano wall; 7 is the vacuum pump of the PECVD tube furnace system, equipped with a vacuum gauge.

Fig. 2 is the structural representation of the room temperature infrared detector based on graphene nano-wall/silicon prepared in embodiment 1, wherein, 1 is copper tape base layer; 2 is liquid gallium indium alloy electrode layer; 3 is N-type silicon sheet layer; 4 is a silicon dioxide layer; 5 is a graphene nano-wall electrode layer; 6 is a silver conductive adhesive electrode layer.

The graphene nanowall is analyzed by Raman spectrum, and the spectrum is shown in Figure 3. From Figure 3, it can be seen that there are obvious characteristic peaks characterizing graphene.

The room temperature infrared detector based on graphene nanowall/silicon was measured in the middle and far infrared test bands, and the test results shown in Figure 4 were obtained, and the photocurrent was significantly greater than the dark current.

Finally, it is noted that the above preferred embodiments are only used to illustrate the technical solutions of the present utility model without limitation. Although the utility model has been described in detail through the above preferred embodiments, those skilled in the art should understand that it can be described in the form Various changes can be made in the above and in the details without departing from the scope defined by the claims of the present invention.

Claims (7)

1. A room temperature infrared detector based on graphene nano-wall/silicon, characterized in that it comprises liquid gallium-indium alloy electrode layer, N-type silicon sheet layer, silicon dioxide layer, graphene nano-wall electrode layer successively from bottom to top , there is at least one contact between the graphene nanowall and the N-type silicon layer, the contact is the active region of the detector, the thickness of the N-type silicon layer is 10-500 μm, and the thickness of the silicon dioxide layer is 100-500nm, the graphene nano wall electrode layer thickness is 100nm-10μm. 2. A kind of room-temperature infrared detector based on graphene nanowall/silicon according to claim 1, characterized in that, the N-type silicon wafer layer adopts N-type lightly doped single crystal silicon wafer. 3. a kind of room temperature infrared detector based on graphene nano-wall/silicon according to claim 1, is characterized in that, described graphene nano-wall electrode layer cross-sectional area is less than silicon dioxide layer. 4. A room-temperature infrared detector based on graphene nanowall/silicon according to claim 1, wherein the infrared detector detects infrared light at room temperature, and the detection waveband is 1 μm-12 μm. 5. a kind of room temperature infrared detector based on graphene nano-wall/silicon according to claim 1, is characterized in that, also comprises the lower conductive base that is arranged on the liquid gallium indium alloy electrode layer bottom and is arranged on graphene nano-wall electrode The upper conductive substrate on top of the layer. 6. a kind of room temperature infrared detector based on graphene nanowall/silicon according to claim 5, is characterized in that, described lower conductive base is copper tape base layer, and described upper conductive base is silver conductive glue electrode layer. 7. A room-temperature infrared detector based on graphene nanowall/silicon according to claim 5, wherein the upper conductive substrate is arranged outside the active region.