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CN-121977715-A - In-situ temperature sensor based on microcavity-quantum dot coupling system and implementation method

CN121977715ACN 121977715 ACN121977715 ACN 121977715ACN-121977715-A

Abstract

The invention discloses an in-situ temperature sensor based on a microcavity-quantum dot coupling system and an implementation method thereof, and belongs to the field of temperature sensors. The invention solves the problems that the pure quantum dot temperature sensor has poor light field and thermal field locality, low temperature measurement sensitivity and slow response speed, and the existing photon crystal-quantum dot coupling structure cannot adapt to a temperature sensing scene, has high response sensitivity to temperature change, can measure in a larger temperature range, has good robustness and extremely strong expandability and universality, and is compatible with a mature semiconductor micro-nano processing flow. The invention is applied to low-temperature cavity quantum optics, semiconductor chip thermal characterization, biological living body micro-area temperature measurement and the like.

Inventors

  • XU XIULAI
  • CHEN XIQING

Assignees

  • 北京大学

Dates

Publication Date
20260505
Application Date
20260318

Claims (10)

  1. 1. An in-situ temperature sensor based on a microcavity-quantum dot coupling system is characterized by comprising a substrate and a photonic crystal slab; the method comprises the steps of forming a sacrificial layer on a substrate, forming a photonic crystal flat plate on the sacrificial layer, removing the sacrificial layer by wet etching, and suspending the photonic crystal flat plate on the substrate, wherein the photonic crystal flat plate comprises a sensing core layer, quantum dots and a Moire photonic crystal microcavity, wherein a single-layer quantum dot is embedded in the middle of the sensing core layer along the thickness direction to form an active layer, and an air hole array which is used for opening the upper surface and the lower surface, namely a photonic crystal is etched on the active layer to form one or more Moire photonic crystal microcavities; The in-situ temperature sensor is placed at a target temperature measurement point of a sample to be measured, continuous light laser irradiates the in-situ temperature sensor to excite quantum dots to generate fluorescence, a Moire photon crystal microcavity is coupled with the quantum dots to enhance the fluorescence, a fluorescence spectrum is collected to obtain wavelength drift amount, and in-situ temperature of the target temperature measurement point is obtained through conversion.
  2. 2. The in-situ temperature sensor of claim 1, wherein the Mo Erchao lattice structure of the moire photonic crystal microcavity is a superposition of two photonic crystals with the same shape, one photonic crystal is a plurality of air holes with the same diameter in a hexagonal area, six equidistant air holes are distributed around each air hole which is not positioned at the edge, the six equidistant air holes are respectively positioned at the vertex of the same hexagon, the center air hole is taken as a rotation center to twist an angle, and the other photonic crystal is obtained, and the air holes formed by superposition of the two photonic crystals form a Mo Erchao lattice structure.
  3. 3. The in-situ temperature sensor of claim 2, wherein the twist angle is 3.5 ° to 7.2 °.
  4. 4. The in-situ temperature sensor of claim 2, wherein both photonic crystals have lattice constants of 298nm to 314nm and the radius of the air holes is 60nm to 80nm.
  5. 5. The in-situ temperature sensor of claim 1, wherein the thickness d of the sensing core layer satisfies n x d = λ/2, n being the refractive index of the sensing core layer, λ being the reference luminescence wavelength of the quantum dot.
  6. 6. An implementation method of an in-situ temperature sensor based on a microcavity-quantum dot coupling system according to any one of claims 1 to 5, characterized in that the implementation method comprises the following steps: 1) Preparing an in-situ temperature sensor: The method comprises the steps of growing a sacrificial layer on a substrate, growing a sensing core layer on the sacrificial layer, embedding a single-layer self-organizing quantum dot in the middle of the sensing core layer to form an active layer, etching an air hole array which is drilled on the upper surface and the lower surface of the active layer to form one or more Moire photon crystal microcavities, wherein each Moire photon crystal microcavity is a hexagonal area and comprises a plurality of air holes to form a Mo Erchao lattice structure; 2) Placing an in-situ temperature sensor at a target temperature measurement point of a sample to be measured; 3) The continuous light laser irradiates the in-situ temperature sensor to excite the quantum dots to generate fluorescence, and the Moire photon crystal microcavity is coupled with the quantum dots to enhance the fluorescence; 4) When the temperature of the target temperature measurement point to be measured changes, the wavelength of fluorescence drifts; 5) And (3) collecting a fluorescence spectrum to obtain a wavelength drift amount, and converting to obtain the in-situ temperature of the target temperature measurement point.
  7. 7. The method of claim 6, wherein in step 1), alGaAs, alAs, inGaP or InAlP is used as the material of the sacrificial layer, and the thickness is 500nm to 1000nm.
  8. 8. The method of claim 6, wherein in step 1), the sensing core layer is formed of a III-V compound semiconductor having ‌ high electron mobility and direct bandgap ‌ characteristics.
  9. 9. The method of claim 6, wherein the reference temperature is set before measuring the temperature of the sample to be measured, the reference spectrum of fluorescence is measured to obtain the reference luminescence wavelength of the quantum dot, and the conversion relation between the wavelength drift amount and the temperature variation amount is measured.
  10. 10. The method according to claim 9, wherein in step 5), the temperature is obtained based on the obtained wavelength shift amount and the conversion relation between the wavelength shift amount and the temperature change amount.

Description

In-situ temperature sensor based on microcavity-quantum dot coupling system and implementation method Technical Field The invention relates to a temperature sensor, in particular to an in-situ temperature sensor based on a microcavity-quantum dot coupling system and an implementation method thereof. Background In the scenes of micro-nano scale devices, low-temperature cavity quantum optics, biological living micro-areas and the like, the accurate measurement of local in-situ temperature is a core technical requirement, and the current mainstream temperature measurement technology has obvious technical bottlenecks, and can be specifically divided into three types of core prior technical schemes and corresponding inherent defects: The first type is a conventional contact temperature measurement technique, represented by a thermocouple thermometer, in which temperature data is obtained by contact measurement. The method can only measure the whole temperature of the contact part of the sensor and the sample, can only obtain the bottom temperature of the contact of the sample and the sample table in a low-temperature cavity test scene, can not realize in-situ temperature measurement of a micro-area on the surface of the sample and a specific local point position, and can not restore the real temperature state of the area to be measured due to interference of the contact measurement on the distribution of a thermal field of the sample to be measured, thereby completely losing the accuracy advantage in a micro-nano scale temperature measurement scene. The second type is a pure quantum dot temperature sensing technology, and the temperature measurement of micro-nano scale is realized by collecting the change of the luminescence spectrum of the semiconductor quantum dot by utilizing the characteristic that the energy level state of the semiconductor quantum dot changes along with the temperature, so that the problem of insufficient spatial resolution of the traditional contact type temperature measurement is solved. The technology has the original defects that the light diffusion and heat diffusion effects naturally exist in the environment where the quantum dot is located, the fluorescent signal of the quantum dot can emit to the whole space and cannot be localized at the periphery of the quantum dot, meanwhile, the heat of the point to be measured can be rapidly dissipated to the surrounding environment, so that the in-situ temperature information of the quantum dot is seriously lost, the response sensitivity of the luminescent signal of the quantum dot to temperature change is directly limited, in addition, the fluorescent signal of a pure quantum dot system is weak, the signal to noise ratio is low, the resolving power of the weak temperature change is poor, and high-sensitivity temperature measurement cannot be realized. The third type is the existing photonic crystal-quantum dot coupling sensing scheme, and the prior art represented by Chinese patent CN103869389A is used for enhancing the far-field emission efficiency of quantum dots through a photonic crystal cascade structure, so as to try to apply the quantum dot coupling sensing scheme to a temperature sensing scene. The scheme is characterized in that a short plate is a core technology, a two-dimensional photonic crystal cascade structure is adopted, the high quality factor Q and the ultra-low mode volume V can not be achieved, the light field local area capacity is limited, only the fluorescence enhancement of the quantum dots can be achieved, the temperature measurement sensitivity is improved to a very low extent, the scheme is optimized only for the far field emission efficiency of the quantum dots, the coupling adaptation of the photonic crystal structure and the quantum dots is not carried out for a temperature sensing scene, the spectral response linearity caused by temperature change is poor, and the temperature measurement interval is limited. Disclosure of Invention Aiming at the problems existing in the prior art, the invention provides an in-situ temperature sensor based on a microcavity-quantum dot coupling system and an implementation method thereof, and solves the problems that the pure quantum dot temperature sensor has poor light field and thermal field locality, low temperature measurement sensitivity and low response speed, and the existing photonic crystal-quantum dot coupling structure cannot be adapted to a temperature sensing scene. An object of the present invention is to provide an in-situ temperature sensor based on microcavity-quantum dot coupling system. The in-situ temperature sensor based on the microcavity-quantum dot coupling system comprises a substrate and a photonic crystal flat plate, wherein a sacrificial layer is formed on the substrate, the photonic crystal flat plate is formed on the sacrificial layer, the sacrificial layer is removed through wet etching, the photonic crystal flat plate is suspended on the substrate