Broadband, high-speed and high-sensitivity comprehensive two-dimensional photoelectric detector based on interface state induction grid control

Abstract

The invention discloses a broadband, high-speed and high-sensitivity comprehensive two-dimensional photoelectric detector based on interface state induction grid control. The photoelectric detector sequentially comprises a two-dimensional material film layer serving as a light absorption layer, an intrinsic oxide layer interface serving as an insulating layer and a channel material layer serving as a reading layer from bottom to top, a source and drain electrode is arranged on the upper surface of the channel material layer, and good electrical contact is formed between the source and drain electrode and the channel material layer; a fixed bias voltage is applied between the source electrode and the drain electrode, when light enters, photon-generated carriers are generated in the two-dimensional material film layer, the photon-generated carriers are effectively separated in a built-in electric field at the interface of the intrinsic oxide layer, electrons in the photon-generated carriers move towards the interior of the two-dimensional material film layer, and the two-dimensional material film layer is formed. Holes in photon-generated carriers are localized at the interface of the intrinsic oxide layer, and signal detection is realized by regulating and controlling the conductivity of the channel material layer; the photoelectric detector provided by the invention can realize broadband, high-speed and high-sensitivity light detection from visible light to near infrared light.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic devices, and in particular is a wide-band, high-speed, high-sensitivity, full-two-dimensional photoelectric detector based on interface state induced gate control. Background Art

[0002] In the field of optoelectronic device technology, light-induced gate-controlled photodetectors have attracted much attention due to their unique gain mechanism. These detectors use the light-induced gate-controlled effect generated by the confinement of photogenerated carriers to achieve efficient control of carriers. In this process, a specific type of carrier is captured by defects inside the material, while another type of carrier circulates multiple times in the channel under the action of external bias, resulting in significant optical gain. The gain can be quantified by the formula G = τ r / τ T To describe, where τ r represents the carrier lifetime, and τ T This relationship shows that the extension of carrier lifetime will lead to an increase in photoconductivity gain, but it will also reduce the response speed of the detector, which constitutes a trade-off in practical applications. Summary of the invention

[0003] Purpose of the invention: In order to solve the problem that existing photoelectric detectors cannot simultaneously meet the requirements of wide-band, high-speed and high-sensitivity detection, the present invention proposes a wide-band, high-speed and high-sensitivity full two-dimensional photoelectric detector based on interface state induced gate control.

[0004] Technical solution: A wide-band, high-speed, high-sensitivity, all-two-dimensional photodetector based on interface state induced gate control, which includes, from bottom to top: a two-dimensional material thin film layer as a light-absorbing layer, an intrinsic oxide layer interface as an insulating layer, and a channel material layer as a readout layer; source and drain electrodes are arranged on the upper surface of the channel material layer, and the source and drain electrodes form good electrical contact with the channel material layer;

[0005] A fixed bias is applied between the source and drain electrodes. When light is incident, photogenerated carriers are generated in the two-dimensional material thin film layer. The photogenerated carriers are effectively separated by the built-in electric field at the interface of the intrinsic oxide layer. The electrons in the photogenerated carriers move into the two-dimensional material thin film layer, and the holes in the photogenerated carriers are localized at the interface of the intrinsic oxide layer. Signal detection is achieved by regulating the conductivity of the channel material layer.

[0006] Furthermore, the two-dimensional material thin film layer is a material layer having absorption characteristics for optical signals in a wide spectral range from visible light to near-infrared light.

[0007] Furthermore, the intrinsic oxide layer interface is an interface formed by surface oxidation treatment of the two-dimensional material thin film layer.

[0008] Furthermore, the channel material layer is a channel material layer with high electron mobility.

[0009] Furthermore, the two-dimensional material thin film layer is a bismuth oxide selenium thin film layer.

[0010] Furthermore, the channel material layer is a graphene layer.

[0011] Furthermore, the surface oxidation treatment includes ultraviolet ozone oxidation treatment.

[0012] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0013] (1) The present invention utilizes interface state induced gating technology to avoid the transfer of carriers between different materials, thereby significantly improving the response speed; combined with the high κ insulating layer, high mobility of the channel material, strong light absorption rate of the two-dimensional material film and wide spectrum response characteristics, the photodetector proposed in the present invention can achieve wide-band, high-speed, and high-sensitivity light detection from visible to near-infrared;

[0014] (2) The photodetector proposed in the present invention utilizes the interface state between the two-dimensional material film and the insulating layer to achieve efficient conversion and rapid response to optical signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the structure of a wide-band, high-speed, high-sensitivity, full-two-dimensional photodetector based on interface state induced gating proposed by the present invention;

[0016] Figure 2 A schematic diagram of the response of a wide-band, high-speed, high-sensitivity, full-two-dimensional photodetector based on interface state induced gating at different wavelengths proposed in the embodiment;

[0017] Figure 3 A schematic diagram of the response speed of a wide-band, high-speed, high-sensitivity, full-two-dimensional photodetector based on interface state induced gating proposed in an embodiment;

[0018] Figure 4 A schematic diagram of the variation of the photoresponsivity of a wide-band, high-speed, high-sensitivity, fully two-dimensional photodetector based on interface state induced gating with power proposed in an embodiment. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is now further described in conjunction with the accompanying drawings and embodiments.

[0020] like Figure 1As shown, this embodiment discloses a wide-band, high-speed, high-sensitivity full two-dimensional photodetector based on interface state induced gating, which includes from bottom to top: a two-dimensional material film 1, an insulating layer 2 and a channel material 3, wherein the interface between the two-dimensional material film 1 and the insulating layer 2 is a natural oxide layer formed by surface oxidation treatment, and the interface has an intrinsic interface state. In this embodiment, the insulating layer 2 is formed by surface oxidation of the two-dimensional material film 1 by means of ultraviolet ozone and the like, and has a high dielectric constant and good interface quality; the channel material 3 is placed above the insulating layer 2, and has a high carrier mobility, and source-drain electrodes 4 are horizontally spaced apart on the upper surface of the channel material 3, and the source-drain electrodes 4 form a good electrical contact with the channel material 3.

[0021] The insulating layer 2 of this embodiment adopts high κ material to enhance the interface electric field and improve the carrier separation efficiency. The two-dimensional material film 1 adopts a material with wide spectrum absorption characteristics to achieve efficient conversion of optical signals in a wide spectrum range from visible light to near-infrared light. Therefore, the two-dimensional material film 1 can be a material such as bismuth oxide selenium that has good absorption of visible to near-infrared light and has a wide spectrum response characteristic. The channel material 3 of this embodiment can be a channel material with high electron mobility such as graphene. The source and drain electrodes 4 can be made of a material with good conductivity such as gold, titanium, nickel or platinum, such as nickel / gold or palladium / gold.

[0022] In this embodiment, the two-dimensional material film 1 is used as the light absorption layer, and the channel material 3 is used as the readout layer. The high electron mobility of the channel material 3 is used to quickly respond to the change of photogenerated carriers, thereby realizing high-speed signal detection. The specific working principle is: a fixed bias voltage V is applied between the source and drain of the photodetector proposed in this embodiment. ds When incident light irradiates the surface of the photodetector, the two-dimensional material film 1 acts as a light-absorbing layer. After the photogenerated carriers are generated in the two-dimensional material film 1, they are effectively separated by the built-in electric field at the interface between the insulating layer 2 and the two-dimensional material film 1. This separation action causes one type of carrier (electron) to move into the interior of the two-dimensional material, and the other type of carrier (hole) is localized at the interface, that is, it is localized at the interface, inducing a change in conductivity in the channel material 3, forming an additional gate voltage, and realizing signal detection by regulating the conductivity of the channel material 3. Under the action of a fixed bias voltage, the change in conductivity is manifested as a source-drain collection current I ds The effect of the interface state induced gating is determined by reading the current between the source and drain electrodes 4. Compared with the conventional light induced gating, the interface state induced gating used in this embodiment does not involve direct charge transfer, which not only helps to achieve high-speed response, but also maintains high-sensitivity light detection performance. At the same time, this embodiment uses a two-dimensional material film 1 as a light absorption layer to achieve wide-band photoelectric detection.

[0023] Figure 2The responsivity (normalized) of the photodetector proposed in this embodiment under illumination of different wavelengths is given. In the wavelength range of 633nm-1450nm, the photodetector has an obvious response.

[0024] Figure 3 The response speed of the device at 633nm light at 10μW is given, and the rise time can reach 6.4μs.

[0025] Figure 4 The variation trend of the responsivity of the photodetector proposed in this embodiment with the light power is given. Under the weak light of 0.1nW, the device responsivity can reach 10 4 A / W.

[0026] The photoelectric detector proposed in this embodiment can simultaneously meet the requirements of wide-band, high-speed, and high-sensitivity detection, and can be prepared according to the following steps:

[0027] Step 1: Grow high-quality bismuth oxide selenide single crystals by chemical vapor deposition;

[0028] Step 2: Oxidizing the bismuth oxide selenium single crystal by ultraviolet ozone to form an intrinsic oxide layer interface;

[0029] Step 3: Transfer the mechanically exfoliated graphene monolayer onto the oxide layer;

[0030] Step 4: Prepare source and drain electrodes by electron beam lithography (EBL) and thermal evaporation.

Claims

1. A wide-band, high-speed, high-sensitivity, all-two-dimensional photodetector based on interface state induced gating, characterized in that: The method comprises, from bottom to top, a two-dimensional material thin film layer as a light absorbing layer, an intrinsic oxide layer interface as an insulating layer, and a channel material layer as a readout layer; source and drain electrodes are arranged on the upper surface of the channel material layer, and the source and drain electrodes form good electrical contact with the channel material layer; A fixed bias is applied between the source and drain electrodes. When light is incident, photogenerated carriers are generated in the two-dimensional material thin film layer. The photogenerated carriers are effectively separated by the built-in electric field at the interface of the intrinsic oxide layer. The electrons in the photogenerated carriers move into the two-dimensional material thin film layer, and the holes in the photogenerated carriers are localized at the interface of the intrinsic oxide layer. Signal detection is achieved by regulating the conductivity of the channel material layer.

2. A wide-band, high-speed, high-sensitivity, full-two-dimensional photodetector based on interface state induced gating control according to claim 1, characterized in that: The two-dimensional material thin film layer is a material layer having absorption characteristics for optical signals in a wide spectral range from visible light to near infrared light.

3. The wide-band, high-speed, high-sensitivity, full-two-dimensional photodetector based on interface state induced gating control according to claim 1, characterized in that: The intrinsic oxide layer interface is an interface formed by surface oxidation treatment of the two-dimensional material thin film layer.

4. The wide-band, high-speed, high-sensitivity, full-two-dimensional photodetector based on interface state induced gating control according to claim 1, characterized in that: The channel material layer is a channel material layer with high electron mobility.

5. The wide-band, high-speed, high-sensitivity, full-two-dimensional photodetector based on interface state induced gating control according to claim 2, characterized in that: The two-dimensional material thin film layer is a bismuth oxide selenium thin film layer.

6. The wide-band, high-speed, high-sensitivity, full-two-dimensional photodetector based on interface state induced gating control according to claim 4, characterized in that: The channel material layer is a graphene layer.

7. The wide-band, high-speed, high-sensitivity, full-two-dimensional photodetector based on interface state induced gating control according to claim 5, characterized in that: The surface oxidation treatment includes ultraviolet ozone oxidation treatment.

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