CN216488081U - Near-infrared response thermal electron photoelectric detector - Google Patents

Abstract

The utility model discloses a thermal electron photodetector with near-infrared response. The thermal electron photodetector comprises a first electrode layer thin film, a first electrode connecting layer thin film, a substrate, a metal connecting layer and a metal layer arranged from bottom to top. A thin film and a one-dimensional photonic crystal; the metal layer thin film is provided with a second electrode; the one-dimensional photonic crystal is formed by a uniform thin film medium periodically alternately arranged. The thermionic photodetector can effectively expand the near-infrared absorption capability of the silicon-based photodetector device, and realize an effective response in the near-infrared wavelength region.

Description

A near-infrared responsive thermionic photodetector

technical field

The utility model relates to photoelectric detection, in particular to a thermal electron photoelectric detector with near-infrared response.

Background technique

As a kind of optical sensor, photodetectors can convert optical signals into electrical signals, and are widely used in military and national economy, such as aerospace, optical communication, industrial control, near-infrared imaging and other fields, such as optical fiber communication, Biometric pattern recognition, unmanned and unmanned aerial vehicles, optocouplers and other technologies.

Among them, silicon (Si) materials are widely used in optical devices in the visible light band due to their advantages of low cost, high purity, mature micro-nano processing technology, high integration, and good device characteristics. However, since the forbidden band width of Si is 1.12 eV and the absorption spectrum is cut off at 1100 nm, the absorption wavelength range of Si is between 400 nm and 1100 nm, which cannot be directly applied to near-infrared photodetection.

Utility model content

The purpose of this utility model is to overcome the above-mentioned problems, and to provide a near-infrared-responsive thermionic photodetector, which can effectively expand the near-infrared absorption capability of the silicon-based photoelectric detection device and realize the near-infrared wavelength region. a valid response.

The purpose of the present utility model is achieved through the following technical solutions:

A near-infrared response thermionic photodetector, comprising a first electrode layer film, a first electrode connection layer film, a substrate, a metal connection layer, a metal layer film and a one-dimensional photonic crystal arranged from bottom to top; the metal A second electrode is arranged on the layer film.

The working principle of the above NIR-responsive thermionic photodetector is as follows:

The performance of the photodetector is optimized by using a one-dimensional photonic crystal based on the traditional metal/Si structure Schottky photodetector. Due to the existence of the TPP mode between the one-dimensional photonic crystal and the metal layer film, when the incident light irradiates the surface of the detector, hot electrons are formed, and the hot electrons are injected into the Si substrate to form a photocurrent, thereby significantly improving the thermal electron photodetector in the near-infrared band. Absorb responsiveness.

In a preferred solution of the present invention, the one-dimensional photonic crystals are formed by periodically alternately arranging uniform thin film media.

Further, the thin film medium of the one-dimensional photonic crystal is TiO ₂ and SiO ₂ .

In a preferred solution of the present invention, the one-dimensional photonic crystal has an arrangement period of 5 to 10 periods, and each period includes a layer of TiO ₂ thin film and a layer of SiO ₂ thin film; the period of the one-dimensional photonic crystal is The thickness is 364nm to 424nm.

Further, the thickness of one layer of TiO ₂ thin film is 146 nm to 171 nm; the thickness of one layer of SiO ₂ thin film is 218 nm to 253 nm.

The selection of the absorption wavelength of the photodetector can be achieved by adjusting the number of periods of the one-dimensional photonic crystal, the thickness of the TiO ₂ film and the thickness of the SiO ₂ film in the period. Effective control of optimal absorption rate.

In a preferred solution of the present invention, the substrate is a single crystal Si wafer; the metal connection layer is a Ti film with a thickness of 0.5 nm; the metal layer is an Au film with a thickness of 10 nm to 35 nm.

In a preferred solution of the present invention, the first electrode connecting layer is a Ti film with a thickness of 30 nm to 50 nm; the first electrode layer is an Au film with a thickness of 20 nm to 100 nm.

Compared with the prior art, the utility model has the following beneficial effects:

On the basis of the traditional metal/Si structure Schottky photodetector, a one-dimensional photonic crystal is used to optimize the performance of the photodetector. Since there is a TPP mode between the one-dimensional photonic crystal and the metal layer film, the incident light irradiates the detector. On the surface, thermionic electrons are formed, and thermionic electrons are injected into the Si substrate to form a photocurrent, thereby significantly improving the absorption response capability of thermionic photodetectors in the near-infrared band, and can be used to detect visible light and near-infrared light with energy lower than the semiconductor band gap.

Description of drawings

1 is a schematic structural diagram of a near-infrared response thermionic photodetector of the present invention.

FIG. 2 is the net absorptivity spectrogram of the photodetector devices with Tamm coupling center wavelengths of 1300 nm, 1400 nm, 1500 nm, 1600 nm and 1700 nm in the first embodiment of the thermionic photodetector of the present invention.

FIG. 3 is a comparison diagram of absorptivity of photodetector devices with different Au layer thicknesses having a center wavelength of 1500 nm according to the first specific embodiment of the thermionic photodetector of the present invention.

FIG. 4 is the responsivity spectrum of the second embodiment of the thermionic photodetector of the present invention under 0V bias and -1V bias.

FIG. 5 is the responsivity spectrum of the third embodiment of the thermionic photodetector of the present invention under 0V bias and -1V bias.

Detailed ways

In order for those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example 1

Referring to FIG. 1 , the near-infrared response thermionic photodetector of this embodiment includes a first electrode layer film 1 , a first electrode connection layer film 2 , a substrate 3 , a metal connection layer 4 , and a metal connection layer 4 , which are sequentially arranged from bottom to top layer film 5 and one-dimensional photonic crystal 6; the metal layer film 5 is provided with a second electrode 51.

In the present embodiment, the one-dimensional photonic crystal 6 is formed by periodically alternately arranging uniform dielectric thin films, and the thin film dielectrics are TiO ₂ (titanium dioxide) and SiO ₂ (silicon dioxide). The arrangement period of the one-dimensional photonic crystal is 5 to 10 periods, and each period includes a layer of _TiO2 film and a layer of _SiO2 film; the thickness of one layer of _TiO2 film is 146nm to 171nm, and the thickness of the one layer of _SiO2 film is 146nm to 171nm. The thickness is 218 nm to 253 nm; the thickness of the one-dimensional photonic crystal period is 364 nm to 424 nm. Wherein, the center wavelength of the forbidden band of the one-dimensional photonic crystal in the one-dimensional photonic crystal period can be adjusted by changing the thickness of the TiO ₂ film and the SiO ₂ film, thereby realizing the absorption rate spectrum of the thermionic photodetector. and modulation of the photoresponse spectrum.

In this embodiment, the metal connection layer 4 is a Ti film with a thickness of 0.5 nm, and the metal layer 5 is an Au film with a thickness of 10 nm to 35 nm. There is a TPP (Tam Plasmonic Polarization) mode between the Au thin film and the one-dimensional photonic crystal. By changing the thickness of the Au thin film, the device absorptivity can be optimized.

The thermionic photodetector device of the present embodiment adopts a multi-layer planar structure, and its specific preparation process is as follows:

(1) The double-polished Si substrate was cleaned, and the Si wafers were placed in acetone and absolute ethanol for ultrasonic cleaning for 15 minutes, then cleaned with deionized water, and then cleaned with buffer oxide etching solution for 30 seconds to remove the Si surface. The oxide layer was finally rinsed with deionized water and blown dry with a nitrogen gun.

(2) One side of the Si sheet is used as the bottom surface, and a mask plate is added to prepare an ohmic contact electrode by magnetron sputtering. First, a Ti film is sputtered as the first electrode connection layer, and then an Au film is sputtered on the Ti film. as the first electrode layer.

(3) A mask plate is added to the other side of the Si sheet, and the Ti film is evaporated by electron beam evaporation as the metal connection layer, and the Au film is evaporated as the metal layer; the Ti layer is used as the connection between the Au film and the Si substrate. The adhesion layer, with a thickness of 0.5 nm, ensures that no ohmic contact is formed between the Au thin film and the Si substrate.

(4) A second mask plate is added on the metal layer, and the TiO ₂ film and the SiO ₂ film are alternately deposited by electron beam evaporation to obtain a one-dimensional photonic crystal. The part covered by the second mask plate will expose the metal layer, and a second electrode is prepared at the edge of the metal layer.

Referring to Figure 2, the peak absorption of the device with the absorption peak wavelength of 1600 nm is 51.5%, and the FWHM is 34 nm; the peak absorption of the device with the absorption peak wavelength of 1300 nm is 39.1%, and the FWHM is 45 nm.

The device structure with the Tamm coupling center wavelength of 1500nm was selected. When the thickness of the Au film was 10nm, 15nm, 20nm, 25nm and 35nm, the differences in the optimal absorption of the device by the thickness of the Au film were compared.

Referring to Figure 3, the thicker the thickness of the Au layer used, the narrower the spectral bandwidth. The absorptivity of the device with Au layer thickness of 35 nm is about 2 times that of 20 nm, and the FWHM is 29 nm.

Example 2

In this embodiment, the thickness of the metal layer Au film is 30 nm; the arrangement period of the one-dimensional photonic crystal is 5 periods, the thickness of a layer of TiO ₂ film in the one-dimensional photonic crystal is 146 nm, and the thickness of a layer of SiO ₂ film is 218nm.

Referring to Figure 4, under -1V bias, the photocurrent responsivity of the device in the 1300nm to 1500nm band reaches 0.01mA/W to 0.1mA/W; at the peak response at the wavelength of 1415nm, under 0V bias and -1V bias The photoresponsivity of 0.08 mA/W and 0.1 mA/W were obtained by pressing down, respectively, and the FWHM was 105 nm.

Example 3:

In this embodiment, the thickness of the metal layer Au film is 30 nm; the arrangement period of the one-dimensional photonic crystal is 6 periods, the thickness of a layer of TiO ₂ film in the one-dimensional photonic crystal is 171 nm, and the thickness of a layer of SiO ₂ film is 253nm.

Referring to Figure 5, under -1V bias, the photocurrent responsivity of the device in the 1505nm to 1625nm band reaches 3.56μA/W to 13μA/W; at the peak response at the wavelength of 1580nm, under 0V bias and -1V bias The lower photoelectric responsivity is 10.4 μA/W and 13 μA/W, respectively, and the FWHM is 60 nm.

The experimental results of the above examples 1, 2 and 3 show that the Si-based thermionic photodetector based on the TPP mode is feasible to work in the near-infrared wavelength range from 1300 nm to 1600 nm, and has obvious photoelectric response.

The above are the preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited by the above-mentioned contents, and any other changes, modifications, substitutions, and combinations made without departing from the spirit and principle of the present utility model , simplification, all should be equivalent replacement methods, and are all included in the protection scope of the present invention.

Claims (10)

1. a thermal electron photodetector of near-infrared response, is characterized in that, comprises the first electrode layer film, the first electrode connection layer film, the substrate, the metal connection layer, the metal layer film and the one-dimensional film arranged from bottom to top A photonic crystal; a second electrode is arranged on the metal layer film. 2 . The near-infrared responsive thermionic photodetector according to claim 1 , wherein the one-dimensional photonic crystals are formed by periodically alternately arranging uniform thin film media. 3 . 3 . The near-infrared responsive thermionic photodetector according to claim 2 , wherein the thin film medium of the one-dimensional photonic crystal is TiO ₂ and SiO ₂ . 4 . 4. The near-infrared responsive thermionic photodetector according to claim 2, wherein the one-dimensional photonic crystal has an arrangement period of 5 to 10 periods, and each period comprises a layer of TiO ₂ film and a layer of SiO ₂ thin film; the thickness of the period of the one-dimensional photonic crystal is 364 nm to 424 nm. 5 . The near-infrared response thermionic photodetector according to claim 4 , wherein the thickness of one layer of TiO ₂ thin film is 146 nm to 171 nm; the thickness of one layer of SiO ₂ thin film is 218 nm to 253 nm. 6 . 6 . The near-infrared response thermionic photodetector according to claim 1 , wherein the substrate is a single crystal Si wafer. 7 . 7 . The near-infrared response thermionic photodetector according to claim 1 , wherein the metal connection layer is a Ti film with a thickness of 0.5 nm. 8 . 8 . The near-infrared responsive thermionic photodetector according to claim 1 , wherein the metal layer is an Au thin film with a thickness of 10 nm to 35 nm. 9 . 9 . The near-infrared responsive thermionic photodetector according to claim 1 , wherein the first electrode connection layer is a Ti film with a thickness of 30 nm to 50 nm. 10 . 10 . The near-infrared responsive thermionic photodetector according to claim 1 , wherein the first electrode layer is an Au thin film with a thickness of 20 nm to 100 nm. 11 .

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