Mid-infrared Photodetectors Research Articles

Гибридный фотоприемник среднего инфракрасного диапазона на основе полупроводниковых квантовых ям

A hybrid mid-infrared photodetector has been implemented, in which silicon carbide (SiC) particles are used to increase the interaction of the electromagnetic field with the electronic subsystem of quantum wells. On the basis of direct measurements of infrared photoconductivity and calculations within the framework of the finite difference method in the time domain, it is shown that this approach makes it possible to increase the sensitivity of such infrared photodetector to electromagnetic radiation by reversing the direction of polarization of the electric field, including in the near zone of SiC particles.

Ferroelectric Superdomain Controlled Graphene Plasmon for Tunable Mid-Infrared Photodetector with Dual-Band Spectral Selectivity

Dual-band infrared photodetectors (DBIPs) can discriminate desired signals from complex scenes and thus are highly expected for threat-warning, remote sensing, and astronomy applications. Conventional DBIPs with high-performances are, however, typically based on semiconductor thin films, but remain the challenges of complex spatial align, expensive growth and cooling requirement. Here, we report a tunable graphene plasmonic photodetector with dual-band infrared spectral selectivity driven by ferroelectric superdomain. The periodic ferroelectric polarization array with nanoscale ring shapes provides ultrahigh electrostatic field for spatially doping of monolayer graphene to desired patterns, and is further used to excite and confine intrinsic graphene plasmons. Our devices exhibit tunable resonance photoresponse in both two bands of 3.7-16.3 um and 15.1-52.1 um. The numerical calculations show that our devices own ultrahigh responsivities of 667-1080 A W-1 at room temperature in range of 5-50 um. Our devices make possible the applications of infrared imaging system and both stationary and motion state of objects detection. These investigations provide a novel approach for advanced infrared system construction by employing simple, low-cost, uncooling multispectral detectors array.

Dual-band perfect absorber for a mid-infrared photodetector based on a dielectric metal metasurface

Mid-infrared thermal detectors have very important applications in the aerospace and military fields. However, due to the low heat transfer efficiency and slow response time, their application has been greatly restricted. Here, we theoretically demonstrate a dual-band perfect absorber for a mid-infrared detector based on a dielectric metal metasurface, and the optical and thermal properties are analyzed in detail. Simulation results show that the two narrow absorption peaks, corresponding to the absorption value of 97.5% at λ = 6.142 μm with λ FWHM ≈ 40 nm and 99.7% at λ = 7.795 μm with λ FWHM ≈ 80 nm , respectively, are achieved, and their different dependences on the structural parameters have been studied. A thermal detector at room temperature with total response time within 1.3 ms for dual-band and 0.4 ms for single-band is realized when the incident light flux is 1.0 W / cm 2 for an average temperature increase of Δ T ≈ 1.0 K . Our study offers a promising approach for designing a narrowband mid-infrared perfect absorber and a high-performance photodetector in nano-integrated photonics.

High-performance mid-infrared photodetection based on Bi2Se3 maze and free-standing nanoplates

The pursuit of optoelectronic devices operating in mid-infrared regime is driven by both fundamental interests and commercial applications. The narrow bandgap (0.3 eV) of layered Bi2Se3 makes it a promising material for mid-infrared photodetection. However, the weak absorption of mid-infrared optical power and high dark current level restrict its performance. Here, a supply-control technique is applied to modulate the growth mode of Bi2Se3 crystal, and Bi2Se3 crystals with various morphologies are obtained. The nanoplates pattern transits from maze to freestanding when source mass was tuned. Due to the strong infrared absorption and photoelectric conversion efficiency of vertical Bi2Se3 nanoplates, the as-prepared vertical Bi2Se3 nanoplates/Si heterojunction shows excellent photoresponse and extremely low dark current. Among these devices based on different Bi2Se3 morphologies, freestanding nanoplates show the optimal mid-infrared characteristics, namely a photo-to-dark ratio of 2.0 × 104, a dark current of 0.21 pA, a response time of 23 ms, a specific detectivity of 6.1 × 1010 Jones (calculated) and 1.2 × 1010 Jones (measured) under 2.7 μm illumination and at room temperature. Notably, the specific detectivity of our devices are comparable to commercial InGaAs photodetectors. With the tunable- morphology growing technique and excellent photoresponding characteristics, Bi2Se3 nanomaterials are worth attention in optoelectronic field.

Comparative study of metamorphic InAs layers grown on GaAs and Si for mid-infrared photodetectors

We report a comparative study of metamorphic InAs p-i-n photodetectors epitaxially grown on GaAs and Si by molecular beam epitaxy. Linearly graded InAlAs buffers were employed to bridge the high lattice mismatch between InAs and Si. Quantitative measurement for threading dislocation density (TDD) in the InAs layers grown on GaAs and Si has been performed using transmission electron microscopy and electron channeling contrast imaging, both of which revealed that the TDD of InAs/Si sample is ~35% higher than that of GaAs sample. Comparison of fabricated InAs p-i-n photodetectors indicated that reduction of threading dislocation density is crucial for low dark current and high responsivity mid-infrared photodetectors on Si.

Zero-bias mid-infrared graphene photodetectors with bulk photoresponse and calibration-free polarization detection

Bulk photovoltaic effect (BPVE), featuring polarization-dependent uniform photoresponse at zero external bias, holds potential for exceeding the Shockley-Queisser limit in the efficiency of existing opto-electronic devices. However, the implementation of BPVE has been limited to the naturally existing materials with broken inversion symmetry, such as ferroelectrics, which suffer low efficiencies. Here, we propose metasurface-mediated graphene photodetectors with cascaded polarization-sensitive photoresponse under uniform illumination, mimicking an artificial BPVE. With the assistance of non-centrosymmetric metallic nanoantennas, the hot photocarriers in graphene gain a momentum upon their excitation and form a shift current which is nonlocal and directional. Thereafter, we demonstrate zero-bias uncooled mid-infrared photodetectors with three orders higher responsivity than conventional BPVE and a noise equivalent power of 0.12 nW Hz−1/2. Besides, we observe a vectorial photoresponse which allows us to detect the polarization angle of incident light with a single device. Our strategy opens up alternative possibilities for scalable, low-cost, multifunctional infrared photodetectors.

Mid‐Infrared Photodetectors: Van der Waals Epitaxial Growth of Mosaic‐Like 2D Platinum Ditelluride Layers for Room‐Temperature Mid‐Infrared Photodetection up to 10.6 µm (Adv. Mater. 52/2020)

In article 2004412, Jiansheng Jie, Yuen Hong Tsang, and co-workers report the epitaxial growth of van der Waals like mosaic-like, 2D platinum ditelluride for highly sensitive room-temperature mid-infrared photodetection. PtTe2/Si Schottky junctions are capable of sensing ultrabroadband light with a wavelength of up to 10.6 μm with a high specific detectivity that is superior to most MIR photodetectors based on 2D layered materials; moreover, their arrays display an excellent room-temperature MIR imaging capability.

Van der Waals Epitaxial Growth of Mosaic-Like 2D Platinum Ditelluride Layers for Room-Temperature Mid-Infrared Photodetection up to 10.6 µm.

Mid-infrared (MIR) photodetection, covering diverse molecular vibrational regions and atmospheric transmission windows, is vital to civil and military purposes. Versatile use of MIR photodetectors is commonly dominated by HgCdTe alloys, InSb, and quantum superlattices, which are limited by strict operation demands, high-cost, and environmental toxicity. Despite the rapid advances of black phosphorus (BP)-based MIR photodetectors, these are subject to poor stability and large-area integration difficulty. Here, the van der Waals (vdW) epitaxial growth of a wafer-scale 2D platinum ditelluride (PtTe2 ) layer is reported via a simple tellurium-vapor transformation approach. The 2D PtTe2 layer possesses a unique mosaic-like crystal structure consisting of single-crystal domains with highly preferential [001] orientation along the normal direction, reducing the influence of interface defects and ensuring efficient out-of-plane carrier transportation. This characteristic, combined with the wide absorption of PtTe2 and well-designed vertical device architecture, makes the PtTe2 /Si Schottky junction photodetector capable of sensing ultra-broadband light of up to 10.6 µm with a high specific detectivity. Also, the photodetector exhibits an excellent room-temperature infrared-imaging capability. This approach provides a new design concept for high-performance, room-temperature MIR photodetection based on 2D layered materials.

Small-scale infrared surround scan system with image motion blur compensation based on multisegment optical wedges

We study an infrared surround scan system based on a photodetector array with an entrance pupil of a small diameter with no specific requirements for achieving versatility and a high dynamic performance. A cooled midinfrared photodetector with an objective and a compensator for the tangential motion blur of an image are housed within a rotating unit. Command and data exchange are ensured using a rotating communication device mounted on a rotation axis of the moving unit. Multisegment assemblies of optical wedges are used instead of single wedges in the compensator for the tangential motion blur of the image. We demonstrate that this engineering design makes it possible to increase the signal integration time by several times compared with a basic design with single-segment wedges.

Plasmonic antenna coupling to hyperbolic phonon-polaritons for sensitive and fast mid-infrared photodetection with graphene

Integrating and manipulating the nano-optoelectronic properties of Van der Waals heterostructures can enable unprecedented platforms for photodetection and sensing. The main challenge of infrared photodetectors is to funnel the light into a small nanoscale active area and efficiently convert it into an electrical signal. Here, we overcome all of those challenges in one device, by efficient coupling of a plasmonic antenna to hyperbolic phonon-polaritons in hexagonal-BN to highly concentrate mid-infrared light into a graphene pn-junction. We balance the interplay of the absorption, electrical and thermal conductivity of graphene via the device geometry. This approach yields remarkable device performance featuring room temperature high sensitivity (NEP of 82 pW/sqrt{{bf{Hz}}}) and fast rise time of 17 nanoseconds (setup-limited), among others, hence achieving a combination currently not present in the state-of-the-art graphene and commercial mid-infrared detectors. We also develop a multiphysics model that shows very good quantitative agreement with our experimental results and reveals the different contributions to our photoresponse, thus paving the way for further improvement of these types of photodetectors even beyond mid-infrared range.

Colloidal Quantum Dot Photovoltaics: Current Progress and Path to Gigawatt Scale Enabled by Smart Manufacturing

Colloidal quantum dots (QDs) have lately been pursued with intense vigor for optoelectronic applications such as photovoltaics (PV), flexible electronics, displays, mid-infrared photodetectors, las...

High oscillator strength interlayer excitons in two-dimensional heterostructures for mid-infrared photodetection.

The development of infrared photodetectors is mainly limited by the choice of available materials and the intricate crystal growth process. Moreover, thermally activated carriers in traditional III-V and II-VI semiconductors enforce low operating temperatures in the infrared photodetectors. Here we demonstrate infrared photodetection enabled by interlayer excitons (ILEs) generated between tungsten and hafnium disulfide, WS2/HfS2. The photodetector operates at room temperature and shows an even higher performance at higher temperatures owing to the large exciton binding energy and phonon-assisted optical transition. The unique band alignment in the WS2/HfS2 heterostructure allows interlayer bandgap tuning from the mid- to long-wave infrared spectrum. We postulate that the sizeable charge delocalization and ILE accumulation at the interface result in a greatly enhanced oscillator strength of the ILEs and a high responsivity of the photodetector. The sensitivity of ILEs to the thickness of two-dimensional materials and the external field provides an excellent platform to realize robust tunable room temperature infrared photodetectors.

Quantum dot based mid-infrared photodetector enhanced by a hybrid metal-dielectric optical antenna

Surface plasmon waves and Rayleigh anomaly are characteristic optical phenomena exhibited by periodic subwavelength grating structures. In this paper, a hybrid metal-dielectric metasurface is proposed to improve the photoresponse of Ge/Si quantum dot infrared photodetectors (QDIPs) with limited absorption layer thickness. The composite metasurface consists of a regular array of silicon pillars. The pillars protrude through subwavelength holes in a perforated gold film on the detector top. We demonstrate that by combining effects of dielectric and plasmonic metal components, the QDIP photoresponse can be significantly improved compared to case when all-dielectric and metal gratings work alone. We observe about four times photoresponse enhancement with the hybrid metasurface device relative to a common plasmonic design with a two-dimensional metal hole array. Compared with a bare QDIP, the peak responsivity of the hybrid detector at a wavelength of 4.4 µm is increased by a factor of 15. The enhanced sensitivity is supposed to arise from coupling of the surface plasmon resonance and diffractive effect related to the Rayleigh anomaly.

Impact of Temperature and Doping on the Performance of ${{\bf Ge}}/{{\bf G}}{{{\bf e}}_{1 - {\boldsymbol{x}}}}{{\bf S}}{{{\bf n}}_{\boldsymbol{x}}}/{{\bf Ge}}$ Heterojunction Phototransistors

We study the effect of temperature and doping in Si-based GeSn heterojunction phototransistors (HPTs) for low-power-consuming, low-cost, and high-speed mid-infrared (MIR) applications. The incorporation of Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> Sn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> alloy in the base of our HPTs significantly shortens the emitter-to-collector transit time, leading to high cut-off frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> ) due to an increase in mobility. Furthermore, the Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> Sn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> base extends the optical detection over a wide range (up to 2500 nm) due to the shrinkage of the bandgap energy caused by alloying with Sn. Additionally, spectral responsivity increases with Sn alloying due to the increased absorption coefficient. Our results show that f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> and responsivity are strongly dependent not only on doping but also on temperature. The impact of temperature on the noise behavior of phototransistors was also analyzed for frequencies up to 100 GHz. As the temperature increased, the signal-to-noise ratio (SNR) decreased; however, spectral responsivity significantly improved. The high SNR, responsivity, and fT values of the GeSn HPT make it a potential candidate for future Si-based uncooled high-speed MIR photodetection.

Synthesis Techniques, Optoelectronic Properties, and Broadband Photodetection of Thin‐Film Black Phosphorus

AbstractBlack phosphorus (BP), a van der Waals (vdW) layered material, has been intensively studied in recent years since the rediscovery of its thin‐film form in 2014. It is considered as a promising material for mid‐infrared (MIR) photodetection, due to its intrinsic narrow bandgap, tunable band properties, decent optical absorption, high room‐temperature mobility, and high compatibility with silicon‐based technology. Here, the recent advances in the synthesis techniques, the novel optoelectronic properties, and applications of thin‐film BP flake in MIR photodetection are reviewed. Over 17 synthesis techniques of BP films, as well as their merits and drawbacks, are summarized and discussed. The recently discovered strain‐, electric‐field‐, and chemical‐doping‐induced bandgap tuning effects in BP effectively extend its optical absorption cutoff wavelength into regime with longer wavelength (&gt;4 µm). In addition, the establishment of BP‐based vdW heterostructures paves a new way to design novel high‐performance MIR photodetectors. BP MIR photodetectors enabled by various photocurrent generation mechanisms (photoconductive, photogating, and photovoltaic effect) and device configurations (transistor‐type, waveguide‐coupled, Schottky‐junction‐type, and heterojunction‐type devices) are summarized and compared.

Ultrahigh-Speed Mid-Infrared Photodetectors With 2-D Electron Gas in a CdTe/PbTe Heterojunction

A CdTe/PbTe heterojunction (HJ) yields two-dimensional electron gas (2DEG) with a high electron density and mobility. Ultrahigh-speed and room-temperature operating mid-infrared photodetectors are developed with the 2DEG. The photoresponse of the detectors originates from the intrinsic response of PbTe by virtue of the conduction-band and valence-band alignment of the HJ. The extremely short rise and decay photoresponse time demonstrate a major advantage of the 2DEG. At $ \lambda = {3.0}\,\, \mu \text{m}$ and a bias voltage of 100 mV, the responsivity and detectivity reach 0.94 A/W and ${2} \times {10}^{{10}}$ Jones, respectively. The excellent performance of the detectors renders promising applications in novel mid-infrared frequency detection systems.

Infrared Nanoimaging of Surface Plasmons in Type-II Dirac Semimetal PtTe2 Nanoribbons.

Topological Dirac semimetals made of two-dimensional transition-metal dichalcogenides (TMDCs) have attracted enormous interest for use in electronic and optoelectronic devices because of their electron transport properties. As van der Waals materials with a strong interlayer interaction, these semimetals are expected to support layer-dependent plasmonic polaritons yet to be revealed experimentally. Here, we demonstrate the apparent retardation and attenuation of mid-infrared (MIR) plasmonic waves in type-II Dirac semimetal platinum tellurium (PtTe2) nanoribbons and nanoflakes by near-field nanoimaging. The attenuated dispersion relations for the plasmonic modes in the PtTe2 nanoribbons (15-25 nm thick) extracted from the near-field standing-wave patterns are applied for the fitting of PtTe2 permittivity in the MIR regime, indicating that both free carriers and Dirac fermions are involved in MIR light-matter interaction in PtTe2. The annihilation of plasmonic modes in the ultrathin (<10 nm) PtTe2 is observed and analyzed, which manifests no near-field resonant pattern due to the intrinsic layer-dependent optoelectronic properties of PtTe2. These results could pave a potential wave for MIR photodetection and modulation with TMDC semimetals.

Influence of GaAs and GaSb substrates on detection parameters of InAs/GaSb superlattice-based mid-infrared interband cascade photodetectors.

The paper presents electrical and optical properties of interband cascade infrared photodetectors with InAs/GaSb type-II superlattice absorbers. We compare the detection parameters of detectors grown on the native GaSb substrate and lattice-mismatched GaAs substrate and seek solutions to enhance device performance, specifically with using an optical immersion. The detectors grown on GaAs have better detection parameters at room temperature, but, at lower temperatures, the misfit dislocations become more important, and detectors grown on GaSb become better.

Upside-down InAs/InAs1-xSbx type-II superlattice-based nBn mid-infrared photodetectors with an AlGaAsSb quaternary alloy barrier.

Ga-free InAs/InAsSb type-II superlattices (T2SLs) are emerging as candidate materials for high temperature operation of mid-infrared photodetectors, which are critical for infrared technology with an aim to provide low-cost and compact detection systems. In this work, by utilizing upside-down device structure, a closely lattice-matched Al0.83Ga0.17AsSb quaternary alloy as electron barrier was pre-grown before the growth of InAs/InAsSb T2SLs absorber in a nBn device. Based on this design, we have demonstrated 5-µm cut-off mid-wavelength infrared (MWIR) photodetectors that exhibited a dark current density of 1.55 × 10-4 A/cm2 at an operation bias 400mV at 150K. A saturated quantum efficiency at ∼4.0 µm reaches 37.5% with a 2 µm absorber and the peak responsivity reaches 1.2 A/W, which yields a peak specific detectivity as high as ∼1.82 × 1011 cm·H z1/2/W at a forward bias of 400mV.

Design and Analysis of Ge/Ge1-xSnx/Ge Heterojunction Phototransistor for MIR Wavelength Biological Applications

This work presents the influence of lateral scaling such as emitter layer thickness and base layer thickness on the responsivity spectra and frequency response of Ge/ Ge1-x Snx/Ge p-n-p heterojunction phototransistor (HPT), a generalized detector for biological sensing and defense applications. The proposed structure contains Ge1-x Snx alloy in the base layer, allowing extension of the photodetection to the mid-infrared (MIR) applications. The study takes account of the effect of base-emitter voltage and Sn concentration on the frequency performance of the HPT. In addition, we have also estimated gain as a function of lateral scaling of the HPT. The calculated results show that cutoff frequency (fT)and maximum frequency (fmax) are not only strongly dependent on the lateral scaling of HPT but also on the Sn concentration and applied base-emitter voltage. Furthermore, gain is less dependent on the emitter layer thickness, however, it is strongly dependent on the base layer thickness. With the GeSn base (with Sn = 9%), fT > 65 GHz for the optimized emitter and base layer thickness of 100 nm and 50 nm, respectively, can be achieved compared with that of InGaAs based HPT. The proposed GeSn HPT exhibits the high spectral responsivity >100 A/W at 1550 nm and >32 A/W at 2100 nm and response time ~2.41 ps. Therefore, the proposed HPT may open up a potential candidate for mid-infrared photodetection in bio-sensing applications.