CN111947792B - Color detection system based on palladium diselenide/ultrathin silicon/palladium diselenide Schottky junction and preparation method thereof - Google Patents

Abstract

The invention discloses a color detection system based on palladium diselenide/ultra-thin silicon/palladium diselenide Schottky junction and a preparation method thereof. The upper and lower surfaces of a glass substrate are symmetrically arranged with two diselenide The palladium film and the n-type ultra-thin silicon wafer constitute a pair of color detection units of the metal-semiconductor metal Schottky junction. The detectable wavelength range of the color detection system of the present invention includes 460-810 nm, which spans the entire visible light region and involves a part of the near-infrared band, and the system has the advantages of high accuracy and repeatability.

Description

A color detection system based on palladium diselenide/ultrathin silicon/palladium diselenide Schottky junction system and preparation method thereof

technical field

The invention belongs to the technical field of photoelectric detection, and in particular relates to a color detection system and a preparation method thereof.

Background technique

A photodetector is an optoelectronic device that converts an optical signal into an electrical signal through the photoelectric effect, and its essence is the change in the conductivity of the light-absorbing material due to the action of light radiation. It is widely used in civil or military fields such as ray measurement and detection, industrial automation control, missile guidance, and night vision technology. According to the application range of detectors, photodetectors can be divided into ultraviolet photodetectors (wavelength 10-400nm), visible photodetectors (400-780nm) and infrared photodetectors (780nm-20μm).

Color detectors are a type of photodetectors, which can not only detect optical signals, but also effectively identify wavelengths. Low-cost high-performance color detectors have important application value in many scientific research and industrial technology fields such as artificial intelligence assisted driving, image sensing, optical communication, fire detection, biomedical imaging, environmental monitoring, space detection and security detection. received widespread attention.

At present, in the widely used visible-near-infrared light band (wavelength <1100nm), photodetectors based on crystalline silicon occupy the main market share. As an important semiconductor material, silicon has been driving the progress of the semiconductor industry. However, due to the excessive thickness of silicon, it is not suitable for integration with infrastructures of various shapes and sizes, which brings great inconvenience to the development of photodetectors. Based on higher requirements for light weight and flexibility, ultra-thin silicon wafers are slowly entering research. In addition, for minority carriers with short diffusion lengths, the use of thinner silicon substrates helps reduce electron-hole recombination, which is also an advantage. At present, photodetectors composed of a single ultra-thin silicon wafer are generally studied. The research angle is too limited and the research scope is too narrow, which restricts the further development and wide application of silicon-based photodetectors. On the other hand, a single photodetector can only realize the detection of light signals, but cannot realize the identification of light wavelengths, which seriously hinders its wide application in scientific research, industrial production and people's life.

SUMMARY OF THE INVENTION

In order to avoid the shortcomings of the above-mentioned prior art, the present invention provides a color detection system based on palladium diselenide/ultra-thin silicon/palladium diselenide Schottky junction, which can effectively identify the detected light wavelength.

The present invention adopts following technical scheme for realizing purpose:

A color detection system based on palladium diselenide/ultra-thin silicon/palladium diselenide Schottky junction is characterized in that it includes a glass substrate, and two colors are symmetrically arranged on the upper and lower surfaces of the glass substrate detection unit;

The color detection unit includes an n-type ultra-thin silicon wafer fixed on the surface of the glass substrate, and a pair of palladium diselenide films are laid on the n-type ultra-thin silicon wafer; one side of the two palladium diselenide films is The area beyond the n-type ultra-thin silicon wafer is located on the glass substrate, and a palladium diselenide contact electrode is arranged in the exceeding area; in the color detection unit, two palladium diselenide films and n-type ultra-thin silicon wafers form metal-semiconductor metal Schottky junctions;

When light irradiates the color detection system layer by layer from above the upper color detection unit (the color detection unit located on the upper surface of the glass substrate), the current ratio between the upper color detection unit and the lower color detection unit varies with the detected color. The wavelength of light decreases as the wavelength of light increases, so that the wavelength of the detected light can be identified according to the current ratio.

Further, the thickness of the glass substrate is 0.8-1 mm.

Further, the n-type ultra-thin silicon wafer is an n-type lightly doped silicon wafer with a thickness of 15-25 μm and a resistivity of 1-7Ω·cm.

Further, the thickness of the palladium diselenide film is 15nm-40nm.

Further, the palladium diselenide contact electrode is a conductive silver paste electrode.

The preparation method of the color detection system of the present invention comprises the following steps:

Step 1. Place the n-type ultra-thin silicon wafer in a hydrofluoric acid solution or BOE etching solution with a mass concentration of 5%-10% for 5-10 minutes, remove the natural oxide layer on the surface, and clean it after taking it out. and dried;

step 2, fixing the n-type ultra-thin silicon wafer processed in step 1 to the upper surface of the cleaned glass substrate;

Step 3. Lay a pair of palladium diselenide films on the n-type ultra-thin silicon wafer; one side of the two palladium diselenide films respectively extends beyond the area of the n-type ultra-thin silicon wafer and is located on the glass substrate ;

Step 4. Drop silver paste electrodes on the areas where the two palladium diselenide films extend beyond the n-type ultra-thin silicon wafer respectively, that is, form a color detection unit on the upper surface of the glass substrate;

Step 5. According to the same method as in Steps 1 to 4, the same color detection unit is formed on the lower surface of the glass substrate, and the two color detection units are completely symmetrical with respect to the glass substrate, that is, a color detection system is obtained.

Compared with the prior art, the beneficial effects of the present invention are embodied in:

1. The present invention designs a color detection system based on palladium diselenide/ultra-thin silicon/palladium diselenide Schottky junction, which is composed of two palladium diselenide/palladium diselenide Ultra-thin silicon/palladium diselenide Schottky junction color detection unit is combined. The wavelength range that the system can detect includes 460-810nm, spanning the entire visible light region and involving a part of the near-infrared band, and the system has accuracy and repeatability The advantage of high sex.

2. The color detection system of the present invention has a simple preparation process and low cost.

Description of drawings

FIG. 1 is a schematic structural diagram of the color detection system based on the PdSe ₂ /ultra-thin silicon/PdSe ₂ Schottky junction of the present invention.

Fig. 2 is the color detection system obtained in Example 1 of the present invention, under the illumination with a wavelength of 400-1300 nm and an intensity of 100 μW/cm ² , under the detection conditions of a temperature of 300K and a bias voltage of 0V, the color detection unit (I _p1 in the figure) is installed. ) and the photocurrent-wavelength characteristic curve (Fig. 2(a)) and the photocurrent ratio (I _p1 /I _p2 )-wavelength curve (Fig. 2(b)) of the lower color detection unit (I _p2 in the figure);

Fig. 3 is the color detection system obtained in Example 1 of the present invention, under the illumination with the wavelength of 400-1300nm and the intensity of 100μW/ ^cm2 , under the 0V bias voltage and different detection temperatures (280K, 300K, 320K), the color detection The photocurrent ratio of the unit and the lower color detection unit (lg(I _p1 /I _p2 ))-wavelength curve comparison diagram;

Figure 4 shows the color detection system obtained in Example 1 of the present invention under the illumination of wavelengths of 480, 520, 560, 600, 660, 700, and 740 nm and the wavelengths of 5 nm above and below (the intensity is 100 μW/cm ² ), at temperatures of 300K, 0V Under the detection condition of bias voltage, the photocurrent ratio (I _p1 /I _p2 )-wavelength curve of the upper color detection unit and the lower color detection unit;

Reference numerals in the figure: 1 is a glass substrate; 2 is an n-type ultra-thin silicon wafer; 3 is a palladium diselenide film; 4 is a palladium diselenide contact electrode.

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention will be described in detail below with reference to the embodiments. The following contents are only examples and descriptions of the concept of the present invention. Those skilled in the art can make various modifications or supplements to the described specific embodiments or replace them in a similar manner, as long as they do not deviate from the concept of the invention. Or beyond the scope defined by the claims, shall belong to the protection scope of the present invention.

Example 1

As shown in FIG. 1 , the color detection system based on PdSe/ultra-thin silicon/Palladium diselenide Schottky junction in this embodiment includes a glass substrate 1 , which is symmetrically arranged on the upper and lower surfaces of the glass substrate 1 There are two color detection units;

The color detection unit includes an n-type ultra-thin silicon wafer 2 fixed on the surface of the glass substrate, and a pair of palladium diselenide films 3 are laid on the n-type ultra-thin silicon wafer 2; one side of the two palladium diselenide films 3 The regions beyond the n-type ultra-thin silicon wafer 2 are located on the glass substrate 1, and a palladium diselenide contact electrode 4 is arranged in the exceeding region; in the color detection unit, two palladium diselenide films and n - type ultra-thin silicon wafers form metal-semiconductor metal Schottky junctions.

Specifically, in this embodiment: the thickness of the glass substrate 1 is 1 mm; the n-type ultra-thin silicon wafer 2 is an n-type lightly doped silicon wafer with a thickness of 20 μm and a resistivity of 5Ω·cm; palladium diselenide The thickness of the thin film 3 is 20 nm; the palladium diselenide contact electrode 4 is a conductive silver paste electrode.

The preparation method of the color detection system of the present embodiment includes the following steps:

Step 1. The n-type ultra-thin silicon wafer is etched in a hydrofluoric acid solution with a mass concentration of 5% for 5 minutes to remove the natural oxide layer on the surface of the n-type ultra-thin silicon wafer. After taking out, use acetone and alcohol in turn. and deionized water for ultrasonic cleaning for 15 minutes each, and blow dry with nitrogen.

Step 2, fixing the n-type ultra-thin silicon wafer processed in step 1 to the upper surface of the cleaned glass substrate.

Step 3, laying a pair of PdSe ₂ films on the n-type ultra-thin silicon wafer; one side of the two PdSe ₂ films respectively extends beyond the region of the n-type ultra-thin silicon wafer and is located on the glass substrate.

Step 4. Drop silver paste electrodes respectively on the regions where the two PdSe ₂ thin films extend beyond the n-type ultra-thin silicon wafer, that is, form a color detection unit on the upper surface of the glass substrate.

Step 5. According to the same method as in Steps 1 to 4, the same color detection unit is formed on the lower surface of the glass substrate, and the two color detection units are completely symmetrical with respect to the glass substrate, that is, a color detection system is obtained.

Figure 2 shows the color detection system obtained in the present embodiment under the illumination with the wavelength of 400-1300 nm and the intensity of 100 μW/cm ² , under the detection conditions of temperature 300K and 0V bias voltage, on the color detection unit (I _p1 in the figure) and The photocurrent-wavelength characteristic curve of the lower color detection unit (I _p2 in the figure) (Fig. 2(a)), and the photocurrent ratio (I _p1 /I _p2 )-wavelength curve (Fig. 2(b)). It can be seen from the figure that when the light illuminates the color detection system layer by layer from above the upper color detection unit, the photocurrent of the upper color detection unit reaches a peak value around 460nm-500nm, and the transmitted light illuminates the lower color detection unit. unit, the lower color detection unit starts to respond at a wavelength of about 800nm-1000nm. However, in the range of 460nm-810nm, the current ratio of the upper color detection unit and the lower color detection unit decreases monotonically with the increase of the wavelength of the detected light, so that the wavelength of the detected light can be identified according to the current ratio. The wavelength range of the probe light can also be controlled by adjusting the thickness of the n-type ultrathin silicon wafer and the palladium diselenide thin film.

Fig. 3 shows the color detection system obtained in this embodiment under the illumination with wavelength of 400-1300nm and intensity of 100μW/ ^cm2 , under 0V bias voltage and different detection temperatures (280K, 300K, 320K), the upper color detection unit and The photocurrent ratio (lg(I _p1 /I _p2 ))-wavelength curve comparison diagram of the lower color detection unit. It can be seen that the detection range of the detection system is broadened at low temperature, which is due to the low thermal excitation in silicon at low temperature. But at different temperatures, the system can achieve accurate detection in the wavelength range of 460nm-810nm.

As shown in FIG. 4 , in order to detect the accuracy of the wavelength detection by the color detection in this embodiment, according to the same detection conditions as shown in FIG. The photocurrent ratio (denoted as (I _p1 /I _p2 ) ₁ ) is compared with the corresponding data in Figure 2 ((I _p1 /I _p2 ) ₀ ), and the relative error is calculated: [(I _p1 /I _p2 ) ₁ -(I _p1 /I _p2 ) ₀ ]/(I _p1 /I _p2 ) ₀ . The results show that the relative errors at wavelengths of 480, 520, 560, 600, 660, 700, and 740 nm are 2.9%, 0.15%, -13.2%, -0.23%, 4.44%, 10.96%, and -6.10%, respectively. It can be seen that the color detection system of this embodiment has very high precision and repeatability in the range of 460-810 nm.

In addition, as shown in FIG. 4 , by performing the same detection at 5 nm wavelengths above and below 480, 520, 560, 600, 660, 700, and 740 nm, it can be seen that the system of this embodiment can still be accurate when the wavelength difference is 5 nm. detection.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the inventive concept thereof shall be included within the protection scope of the present invention.

Claims (6)

1. A color detection system based on palladium diselenide/ultrathin silicon/palladium diselenide Schottky junction is characterized in that: the color detector comprises a glass substrate (1), wherein two color detection units are symmetrically arranged on the upper surface and the lower surface of the glass substrate (1);

the color detection unit comprises an n-type ultrathin silicon wafer (2) with the thickness of 15-25 mu m, which is fixed on the surface of the glass substrate, and a pair of palladium diselenide thin films (3) is paved on the n-type ultrathin silicon wafer (2); one side of each of the two palladium diselenide thin films (3) respectively exceeds the region of the n-type ultrathin silicon wafer (2) and is positioned on the glass substrate (1), and a palladium diselenide contact electrode (4) is arranged in the exceeding region; in the color detection unit, a metal semiconductor metal Schottky junction is formed by two palladium diselenide thin films and an n-type ultrathin silicon wafer;

when the color detection system is irradiated by light from above the upper color detection unit downwards layer by layer, the current ratio of the upper color detection unit to the lower color detection unit is reduced along with the increase of the wavelength of the detected light, so that the wavelength of the detected light can be identified according to the current ratio.

2. The color detection system of claim 1, wherein: the thickness of the glass substrate (1) is 0.8-1mm.

3. The color detection system of claim 1, wherein: the n-type ultrathin silicon wafer (2) is an n-type lightly doped silicon wafer with the resistivity of 1-7 omega cm.

4. The color detection system of claim 1, wherein: the thickness of the palladium diselenide thin film (3) is 15nm-40nm.

5. The color detection system of claim 1, wherein: the palladium diselenide contact electrode (4) is a conductive silver paste electrode.

6. A method of manufacturing a color detection system according to any one of claims 1 to 5, comprising the steps of:

step 1, placing an n-type ultrathin silicon wafer in hydrofluoric acid solution with mass concentration of 5% -10% or BOE etching solution for etching for 5-10 minutes, removing a natural oxide layer on the surface, taking out, cleaning and drying;

step 2, fixing the n-type ultrathin silicon wafer processed in the step 1 on the upper surface of a cleaned glass substrate;

step 3, laying a pair of palladium diselenide films on the n-type ultrathin silicon wafer; one side of each of the two palladium diselenide films respectively exceeds the region of the n-type ultrathin silicon wafer and is positioned on the glass substrate;

step 4, respectively dripping silver paste electrodes on the areas of the two palladium diselenide films, which exceed the n-type ultrathin silicon wafer, namely forming a color detection unit on the upper surface of the glass substrate;

and 5, forming the same color detection units on the lower surface of the glass substrate according to the same method in the steps 1 to 4, wherein the two color detection units are completely symmetrical relative to the glass substrate, and thus obtaining the color detection system.

Images