CN115911157A - Integrated II-class superlattice infrared detector of dual-mode resonance antenna - Google Patents
Integrated II-class superlattice infrared detector of dual-mode resonance antenna Download PDFInfo
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Abstract
The invention provides a class-II superlattice infrared detector integrated with a dual-mode resonance antenna, which comprises a GaSb substrate, an n-type GaSb buffer layer, an n + + InAs n-type lower contact layer, inAs/InAs 0.5 Sb 0.5 T2SL absorption layer, alAsSb barrier layer, inAs/InAs 0.5 Sb 0.5 The invention relates to a T2SL n-type upper contact layer and a comb-shaped metal antenna electrode, which are based on the resonance of a waveguide mode under TE polarization and a local plasma mode under TM polarization, realize the enhancement of the detection performance of a II-type superlattice detector insensitive to polarization, enhance the external quantum efficiency by 8-11 times in the TE and TM polarization directions to 40-55 percent, and solve the problem of insufficient detection efficiency of an ultra-thin type II-type superlattice detectorThe bottleneck problem of (2).
Description
Technical Field
The invention relates to the technical field of infrared detection, in particular to a class-II superlattice infrared detector integrated with a dual-mode resonance antenna.
Background
The infrared detection technology has wide application prospects in the fields of aerial remote sensing, scientific research, communication, medical treatment, gas sensing, imaging and the like, and with the continuous development of the detection technology and the continuous improvement of the requirements of practical application on the performance of the detector, the infrared detector gradually develops towards high sensitivity, miniaturization and integration. The mainstream infrared detection technology at present is a Mercury Cadmium Telluride (MCT) detector, but the mercury cadmium telluride detector still has obvious defects, and the detector has unstable material performance, high preparation cost and poor repeatability. The detector based on antimonide II-type superlattice (T2 SL) is a new infrared technology in recent years, compared with mercury cadmium telluride, the II-type superlattice detector is based on a mature III-V semiconductor technology, has the advantages of good material uniformity, good device stability, long Auger composite life, low dark current and the like, and is considered as a new generation of competitive infrared detection technology.
With the rapid development of material synthesis and device processing technology, the existing II-class superlattice infrared detector has good detection performance, the responsivity reaches A/W magnitude, and the detection rate can reach 10 11 cmHz 1/2 However, limited by the low material absorption coefficient, the quantum efficiency of the device is generally between 10% and 60%, which cannot be compared with the mainstream mercury cadmium telluride detector (70% to 80%). In particular, for ultra-thin type class II superlattice infrared detectors with the thickness of the absorption layer less than 0.5 μm, the quantum efficiency is usually less than 20%, and further development and application of the class II superlattice infrared detectors are limited. In order to improve the quantum efficiency of an ultrathin II-type superlattice infrared detector, the invention provides a dual-mode resonance integrated antenna, which utilizes the resonance of a waveguide mode and a local plasma mode of the antenna to realize the improvement of the absorption and detection efficiency of the detector under two polarization states of TE and TM, improves the quantum efficiency of the device by 8-11 times and reaches up to 40-55 percent, and provides a new antenna integration design scheme for a high-performance II-type superlattice infrared detector.
The existing antenna resonance enhanced class II superlattice detectors mainly utilize periodic metal or dielectric strip antennas. Wang et al have proposed a metal strip array antenna for ultra-thin type class ii superlattice infrared detectors [ see document 1: S.Wang, N.Yoon, A.Kamboj, et al, applied Physics Letters,112,091104 (2018), the structure of which is shown in FIG. 1, the absorption layer (SLS) is InAs/GaSb quantum well superlattice, the thickness is only 180nm, resonance enhanced detection response is realized at the wavelength of 9.15 μm under TM polarization, the external quantum efficiency is close to 50%, and meanwhile, compared with the traditional II-class superlattice detector, the thickness of the absorption layer is reduced by 30 times. Another dielectric strip array antenna has recently been proposed by a.kamboj et al [ see document 2: A.Kamboj, L.Nordin, P.Petluru, et al, applied Physics Letters,118,201102 (2021), the structure of which is shown in FIG. 2, the structure uses InAs/InAsSb quantum well superlattice, the thickness is 280nm, the surface of a detection layer uses periodic medium strips, the detection response is improved at the wavelength of 4.5 μm under TE polarization, and the external quantum efficiency reaches 52.5%.
The antennas used to enhance the performance of the type ii superlattice detectors described above all use a single resonant mode, and their high quantum efficiency can only be achieved in one optical polarization direction (TE or TM polarization), while there is no enhancement effect on the detection performance in the other orthogonal optical polarization direction. For practical detector applications, the detector is generally required to have high detection performance in any light polarization direction, so that the existing antenna enhancement technical scheme based on a single resonance mode has the limitation of sensitivity to the light polarization direction.
Disclosure of Invention
The invention aims to provide a II-type superlattice infrared detector integrated by a dual-mode resonance antenna, which is used for realizing the enhancement of the polarization insensitive detection performance of an ultrathin II-type superlattice detector based on the resonance of a waveguide mode under TE polarization and a local plasma mode under TM polarization, and the external quantum efficiency is enhanced by 8-11 times in the TE and TM polarization directions to reach 40-55%, thereby solving the problem of insufficient detection efficiency of the ultrathin II-type superlattice detector.
In order to achieve the purpose, the invention provides a class II superlattice infrared detector integrated by a dual-mode resonance antenna, which adopts the following technical scheme:
a dual-mode resonant antenna integrated II-type superlattice infrared detector comprises a GaSb substrate, an n-type GaSb buffer layer, an n + + InAs n-type lower contact layer, inAs/InAs 0.5 Sb 0.5 T2SL absorption layer, alAsSb barrier layer, inAs/InAs 0.5 Sb 0.5 A T2SL n-type upper contact layer and a comb-shaped metal antenna electrode.
Further, the thickness of the n-type GaSb buffer layer is 0.05-0.15 μm.
Further, the thickness of the n + + InAs n type lower contact layer is 1-2 μm, and the doping concentration is 1 × 10 19 -3×10 19 cm -3 。
Further, the InAs/InAs 0.5 Sb 0.5 The thickness of the T2SL absorption layer is 0.25-0.35 μm.
Further, the AlAsSb barrier layer is 0.2-0.3 μm thick.
Further, the InAs/InAs 0.5 Sb 0.5 The thickness of the T2SL n-type upper contact layer is 0.01-0.1 mu m.
Further, the length and the period of the comb-shaped metal antenna electrode are determined according to the target detection wavelength.
Further, the resonance wavelengths of the local plasmon mode in TM polarization and the waveguide mode in TE polarization are designed to the same target probe wavelength.
Further, the length L and the period P of the comb-shaped metal antenna electrode satisfy the conditions of L = lambda/2 n and 2 pi/lambda sin theta 0 +2 pi/P = β, where λ is the resonant target detection wavelength, n is the effective refractive index, θ 0 Is the angle of incidence of the probe light.
Further, under the condition of determining the width L and the period P of the comb-shaped metal strip antenna, when TM and TE incident light are polarized, a local plasma mode and a waveguide mode are respectively generated, and the two modes resonate in InAs/InAs of the detector 0.5 Sb 0.5 The T2SL absorption layer generates a strong optical field, so that the interaction between the detector absorption layer and light is effectively enhanced, and the absorption efficiency of the detection light is improved.
The invention has at least the following technical effects:
the invention provides a comb-shaped metal antenna integration scheme of dual-mode resonance for an ultrathin II-type superlattice infrared detector, which has the advantages of high absorption and photoelectric detection efficiency on detection light in all polarization directions, and the quantum efficiency of the detector is improved by 8-11 times and is up to 40-55% compared with a conventional detection structure without a metal antenna under two polarization states of TM and TE, so that the problem of insufficient detection efficiency of the ultrathin II-type superlattice infrared detector is solved.
Drawings
In order to more clearly illustrate the embodiments of the present invention and the technical solutions in the prior art, the following briefly introduces the drawings, which are needed to be used in the description of the embodiments of the present invention and the prior art. Throughout the drawings, like elements or portions are generally identified by like reference numerals. In the drawings, elements or portions are not necessarily drawn to scale.
Fig. 1 shows a metal strip antenna integrated ultra-thin class ii superlattice infrared detector according to the prior art.
Fig. 2 shows a dielectric strip antenna integrated ultra-thin class ii superlattice infrared detector according to the prior art.
Fig. 3 shows a schematic diagram of a comb-shaped dual-mode resonant antenna integrated class ii superlattice infrared detector according to an embodiment of the present invention, wherein: the structure of the waveguide is shown in the following steps of (a) a structure schematic diagram, (b) a local plasma resonance mode in TM polarization, and (c) a waveguide mode in TE polarization.
Fig. 4 shows a schematic diagram of a dual-mode resonant antenna integrated lambda-4.12 μm ultra-thin class ii superlattice infrared detector in accordance with an embodiment of the invention.
Fig. 5 shows the absorption performance and antenna resonance mode of an ultra-thin type class ii superlattice infrared detector according to an embodiment of the present invention, wherein: (a) the total absorption efficiency, (b) the absorption efficiency of the absorbing layer, (c) the field distribution of the waveguide mode in the TE polarization, and (d) the field distribution of the localized plasmon mode in the TM polarization.
Fig. 6 illustrates the detected quantum efficiency (EQE) of an ultra-thin class ii superlattice infrared detector in accordance with an embodiment of the invention.
Detailed Description
The following embodiments of the present invention are provided by specific examples, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure of the present invention. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples.
The embodiment of the invention provides a class-II superlattice infrared detector integrated with a dual-mode resonant antenna, and quantum efficiency of the detector is improved based on waveguide mode resonance of a comb-shaped metal antenna under TE polarization and local plasma mode resonance under TM polarization. The detector structure of the invention is as shown in fig. 3 (a), and comprises a GaSb substrate, a 0.1μm n-type GaSb buffer layer, a 1.5μm n + + InAs n-type lower contact layer, a 0.28μm absorption layer, a 0.15μm AlAsSb barrier layer, a 0.05μm n-type upper contact layer and a comb-shaped metal antenna electrode from bottom to top in sequence. The length and the period of the metal strip of the comb-shaped metal antenna electrode are designed according to a target detection wavelength, and the design principle is that the resonance wavelength of a local plasma mode under TM polarization and the resonance wavelength of a waveguide mode under TE polarization are designed to be the same target detection wavelength, and specifically, the requirements of L = lambda/2 n and 2 pi/lambda sin theta are met 0 +2 pi/P = beta, where L is the width of the metal strip, P is the metal strip period, λ is the resonant target wavelength, n is the effective refractive index, θ is 0 Is the angle of incidence of the probe light. When the width L and the period P of the metal strip antenna are determined according to the above relationship, a local plasmon mode and a waveguide mode are generated when incident light of TM and TE is polarized, respectively, as shown in fig. 3 (b) and 3 (c). The two modes resonate to generate a strong optical field on a 0.28 mu m absorption layer of the detector, the absorption and photoelectric conversion efficiency of the detection light is effectively enhanced, the quantum efficiency improvement in all polarization directions is realized for the ultrathin II-type superlattice infrared detector, and a new method is provided for the high-performance II-type superlattice infrared detector technology.
Class II superlattice infrared detector based on dual-mode resonant antenna integration as described above, in one aspect, the combThe dual-mode resonant antenna is designed, and a local plasma resonant mode and a waveguide mode under TM and TE polarization are used, so that the performance of the detector insensitive to light polarization is enhanced. On the other hand, the design of the n-type lower contact layer has a doping concentration of 1 × 10 or more 19 cm -3 And the thickness is greater than or equal to 1 μm so as to enhance the coupling of the two resonance modes of the absorption layer and the antenna and enhance the detection light absorption efficiency to the maximum extent.
The implementation of the technical scheme and the device effect of the invention are demonstrated by taking an ultrathin InAs/InAsSb II type superlattice detector as an example. The adopted structure is shown in figure 4, and the doping concentration of each layer of material is 1 multiplied by 10 from bottom to top in sequence 17 cm -3 N-type GaSb substrate, 0.1 mu m GaSb buffer layer, 1.5 mu m doping concentration of 2 x 10 19 cm -3 InAs lower contact layer of (1), 0.28 μm InAs/InAs 0.5 Sb 0.5 (19.8/4.2 ML) T2SL absorber layer, 0.15 μm AlAsSb barrier layer, 0.05 μm InAs/InAs 0.5 Sb 0.5 A (19.8/4.2 ML) n-type upper contact layer and a comb-shaped metal antenna electrode. For a target detection wavelength λ =4.12 μm, according to the two-mode resonance conditions L = λ/2n and 2 π/λ sin θ 0 +2 pi/P = β, the width of the antenna strip L =0.48 μm, and the period P =1.76 μm. Under the condition of the dimensional parameters of the antenna, a local plasma mode under TM polarization and a waveguide mode under TE polarization resonate at a target wavelength lambda =4.12 mu m, and the doping concentration at 1.5 mu m is 2 multiplied by 10 19 cm -3 With the aid of InAs lower contact layer, the two resonance modes and 0.28 μm InAs/InAs of the detector 0.5 Sb 0.5 The (19.8/4.2 ML) T2SL absorption layer generates strong coupling, so that the light absorption and detection efficiency of the detector are effectively enhanced, and the improvement of the detection performance with insensitive polarization direction is realized.
FIG. 5 shows the absorption performance and antenna resonance mode of the ultrathin InAs/InAsSb class II superlattice detector. From fig. 5 (a) and (b), it can be seen that the detector has resonance enhanced absorption peaks in both TE and TM polarizations, with a resonance wavelength λ =4.12 μm, total absorption efficiency in both polarizations being 98% and 70%, respectively, while the absorption efficiency of the absorption layer that is dominant for the detection response is 55%, which is improved by 11 times compared to the detector without antenna, with polarization insensitive absorption efficiency enhancement characteristics. Fig. 5 (c) and 5 (d) show the resonant mode field distributions for two polarizations at λ =4.12 μm, respectively. It can be seen that for TE polarization, the metal strip antenna excites a waveguide mode, the optical field thereof is distributed below the metal strip, the maximum electric field coincides with the absorption layer, and the light absorption efficiency of the detector is promoted to be improved; for TM polarization, the metal strip antenna excites a local plasma mode, the maximum optical field of the metal strip antenna is distributed at the left end and the right end of the metal strip, meanwhile, an optical field intensity spot is formed below the metal strip and is overlapped with the absorption layer in space, and the light absorption efficiency of the detector is improved.
FIG. 6 is the External Quantum Efficiency (EQE) of the ultra-thin InAs/InAsSb class II superlattice detectors described above. Under the action of the dual-mode resonance metal strip antenna, the device has an enhanced detection effect at the position of lambda =4.12 μm, the external quantum efficiency of the device under TE and TM polarization reaches 40% and 55% respectively, and the detection performance is obviously improved by 8 times and 11 times compared with a detector without the antenna (the external quantum efficiency is 5%).
In the above embodiment, the ultra-thin InAs/InAsSb ii-type superlattice detector is taken as an example to demonstrate the effect of the technical scheme of the present invention, and polarization-insensitive high-performance infrared detection is obtained at a wavelength λ =4.12 μm, and the external quantum efficiency reaches 40-55%, so that a technical method is provided for performance improvement and practical development of the ii-type superlattice detector. According to the dual-mode resonance principle and working conditions, the technical scheme provided by the invention can be optimally expanded to other wave bands, and is suitable for InAs/InAsSb and InAs/GaSb II-class superlattice detectors in the middle infrared wave band of 3-12 mu m.
The above embodiments are only for illustrating the invention and are not to be construed as limiting the invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention, therefore, all equivalent technical solutions also belong to the scope of the invention, and the scope of the invention is defined by the claims.
Claims (10)
1. Dual-mode resonance antennaAn integrated II-type superlattice infrared detector is characterized by comprising a GaSb substrate, an n-type GaSb buffer layer, an n + + InAs n-type lower contact layer, inAs/InAs 0.5 Sb 0.5 T2SL absorption layer, alAsSb barrier layer, inAs/InAs 0.5 Sb 0.5 T2SL n-type upper contact layer and comb-shaped metal antenna electrode.
2. The integrated class ii superlattice infrared detector as in claim 1, wherein said n-type GaSb buffer layer has a thickness in a range of 0.05-0.15 μm.
3. The integrated class ii superlattice infrared detector of claim 1, wherein said n + + InAs n type lower contact layer has a thickness of 1-2 μm and a doping concentration of 1 x 10 19 -3×10 19 cm -3 。
4. The dual-mode resonant antenna integrated class ii superlattice infrared detector as claimed in claim 1, wherein said InAs/InAs 0.5 Sb 0.5 The thickness of the T2SL absorption layer is 0.25-0.35 μm.
5. The dual-mode resonant antenna integrated class ii superlattice infrared detector as claimed in claim 1, wherein said AlAsSb barrier layer has a thickness of 0.2-0.3 μm.
6. The dual-mode resonant antenna integrated class ii superlattice infrared detector as claimed in claim 1, wherein said InAs/InAs 0.5 Sb 0.5 The thickness of the T2SL n-type upper contact layer is 0.01-0.1 μm.
7. The dual-mode resonant antenna integrated class ii superlattice infrared detector as recited in claim 1, wherein a length and a period of said comb-shaped metal antenna electrode are determined in accordance with a target detection wavelength.
8. The integrated class ii superlattice infrared detector of claim 7, wherein resonant wavelengths of the local plasmon mode under TM polarization and the waveguide mode under TE polarization are designed to a same target detection wavelength.
9. The dual-mode resonant antenna integrated class ii superlattice infrared detector as claimed in claim 7 or 8, wherein a length and a period of said comb-shaped metal antenna electrode satisfy conditions of L = λ/2n and 2 π/λ sin θ 0 +2 pi/P = beta, where L is the width of the comb metal antenna, P is the period of the comb metal antenna, λ is the resonant target detection wavelength, n is the effective refractive index, θ 0 Is the angle of incidence of the probe light.
10. The dual-mode resonant antenna integrated class II superlattice infrared detector as claimed in claim 9, wherein under the condition of determining the width L and the period P of the comb-shaped metal strip antenna, a local plasma mode and a waveguide mode are respectively generated when TM and TE incident light is polarized, and the two modes resonate in InAs/InAs of the detector 0.5 Sb 0.5 The T2SL absorption layer generates a strong optical field, and the absorption efficiency of the detection light is enhanced.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117038756A (en) * | 2023-10-08 | 2023-11-10 | 长春理工大学 | Quantum dot detector with spectrum and polarization selectivity |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117038756A (en) * | 2023-10-08 | 2023-11-10 | 长春理工大学 | Quantum dot detector with spectrum and polarization selectivity |
| CN117038756B (en) * | 2023-10-08 | 2024-04-02 | 长春理工大学 | Quantum dot detector with spectrum and polarization selectivity |
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