High-performance Near-infrared Photodetectors Research Articles

Cation-Exchanged quantum Dot-Based high-performance near-infrared photodetectors through surface treatment and passivation

Cation-exchange (CE) is a straightforward method for synthesizing colloidal quantum dots (CQDs) comprising multiple elements. However, the responsivity of photoconductors using cation-exchanged CQDs remains limited due to surface traps induced by the CE process. In this study a flexible near-infrared (NIR) photoconductive detector that exhibits the high responsivity (457 mA/W) under NIR light compared to reported Ag2Se CQD photodetector is fabricated using partially cation exchanged CdxAg2-xSe CQDs. The as-synthesized CdSe CQDs were transformed into CdxAg2-xSe CQDs through the introduction of an Ag precursor to enhance their NIR absorption characteristics and preserve their cubic structures. To mitigate surface traps associated with cation-exchanged CQDs, solution-phase ligand-exchange and post-treatment for surface passivation are incorporated using InBr3. In and Br ions are utilized to fill the surface vacancies of the CQDs and passivate the dangling bonds, reducing nonradiative recombination sites. Structural and optical analyses confirm the passivation of trap states. In addition, indium passivation improves the Seebeck coefficient and mobility, resulting in enhanced responsivity. This study underscores the importance of surface passivation in the CE method, thereby contributing to the future CQDs development with multiple elements.

High-Performance Near-Infrared Photodetector by Integration of PbS Quantum Dots With 3D-Graphene

Achieving breakthroughs in high-performance near-infrared (NIR) photodetectors (PDs) relies on selecting materials and designing device structures. This work shows the synergistic effect between three-dimensional graphene (3D-graphene) and PbS quantum dots (PbS QDs) in the PD structure design, achieved by in-situ growth of 3D-graphene on the silicon (Si) substrate, followed by PbS QDs modification on the 3D-graphene surface. The high-performance NIR PD based on PbS QDs/3D-graphene/Si heterojunction is realized. The synergistic effect of 3D-graphene with strong light absorption and the effective built-in potential modulation by PbS QDs lead to the high detectivity (1×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> Jones) and responsivity (13.7 A/W) of the as-fabricated PD at 1550 nm.

Photoresponse Improvement of InGaAs Nanowire Near-Infrared Photodetectors with Self-Assembled Monolayers

InGaAs nanowires (NWs) show tremendous potential as channel materials in the field of near-infrared photoelectric detections. However, the abundance of surface states on InGaAs NWs has limited the photoelectronic properties of the devices, and further performance enhancement can be achieved by manipulating NWs surface state charges. In this work, high-quality InGaAs NWs are synthesized by two-step chemical vapor deposition, and high-performance near-infrared photodetectors are achieved based on the as-grown NWs with a large responsivity of 3.7 × 103 A/W, a superior detectivity of 1.01 × 1011 jones, and an external quantum efficiency of 4.34 × 103% under 1064 nm irradiation. More importantly, self-assembled monolayers are employed for the surface modification of InGaAs NW photodetectors using a simple wet chemistry, in which the inorganic (NH4)2S monolayer enhances the sensitivity of the devices by reducing the response time and the organic 1-octadecanethiol monolayer improves the photoresponse of the devices by raising the photocurrent. This work offers significant reference values to modulate the surface states of ternary and multielement NWs and improving the photoelectric performance of nanoscale broadband photodetectors for next-generation advanced optoelectronic devices.

Multilayer α′-4H-borophene growth on gallium arsenide towards high-performance near-infrared photodetector

Multilayer borophene was predicted to have a similar semiconductor property to its monolayer arise from the weak van der Waals interactions between the layers. Besides, multilayer borophene has a higher carrier mobility than monolayer ones, so it is placed great hopes in applications of photoelectric and photovoltaic devices. However, its preparation and application in experiments of multilayer borophene are still lacking. Here, multilayer α′-4H-borophene was synthesized on semiconducting n-type GaAs substrates using NaBH4 source as precursor and hydrogen as the carrier gas under controlled temperature and pressure conditions. The experimental results of the borophene are in good agreement with those of its theoretical prediction. The borophene is a semiconductor with a bandgap of 2.48 eV. To demonstrate the device application potential of the borophene, a near-infrared photodetector composed of p-type borophene and n-type GaAs was fabricated. The photodetector shows a high photoresponsivity of 0.31 mA·W−1, a high specific detectivity of 108 Jones, and a fast response or recovery speed of 117 or 109 ms under the irradiation with the wavelength of 940 nm at zero bias. The results prove that the α′-4H-borophene/GaAs photodetector can show high sensitivity and zero consumption, which is of great value in meeting the appeal of sustainable development of society.

Narrow-bandgap Sn-Pb mixed perovskite single crystals for high-performance near-infrared photodetectors.

Narrow-bandgap Sn-Pb mixed perovskite single crystals are highly promising as photoactive materials for efficient and low-cost near-infrared (NIR) photodetectors. However, because of the significant difference in the crystallization velocities for Pb- and Sn-based perovskites, Sn-Pb mixed perovskites are peculiarly prone to phase separation during the crystallization process, causing the degradation of the optical and electronic properties of materials. Herein, we propose a low-temperature space-confined technique (LT-SCT) that simultaneously reduces the crystallization velocities of pure Sn and Pb perovskites, enabling the fabrication of pure-phase (FASnI3)0.1(MAPbI3)0.9 single crystals. The resulting (FASnI3)0.1(MAPbI3)0.9 single crystals exhibit excellent crystallinity with a high hole mobility of 7.44 × 103 cm2 V-1 s-1 and a low surface trap density of 1.88 × 109 cm-2. These properties benefit the application of (FASnI3)0.1(MAPbI3)0.9 single crystals in self-powered NIR photodetectors and yield outstanding comprehensive performance, especially with a broad linear dynamic range of up to 163.5 dB, a large responsivity (R) of 0.53 A W-1, and a fast response speed of 22.78 μs in the NIR spectral region (750-860 nm). Furthermore, high-quality NIR imaging and wearable health monitoring are achieved by employing high-performance and self-driven NIR photodetectors. This work contributes to developing Sn-Pb mixed perovskite single crystals and provides a promising candidate for efficient and low-cost NIR photodetection.

Overall High-Performance Near-Infrared Photodetector Based on CVD-Grown MoTe2 and Graphene Vertical vdWs Heterostructure

Two-dimensional (2D) materials, such as graphene and transition metal dichalcogenides (TMDCs), are highly appealing in the fields of electronics, optoelectronics, energy, etc. Graphene, with high conductivity and high carrier mobility, is an excellent candidate for transparent electrodes. TMDCs have remarkably strong light absorption in the range of visible to infrared wavelength. High-performance photodetectors are expected to achieve through the combination of graphene and TMDCs. Nowadays, near-infrared (NIR) photodetectors play significant roles in many areas. MoTe2 with bandgap energy of about 1.0 eV in its bulk form is a promising material for cost-saving NIR photodetectors. Thus far, only a few of the reported studies on NIR photodetectors built on MoTe2/graphene heterostructures have achieved high responsivity and short response time simultaneously in one device. In this study, we fabricate graphene–MoTe2–graphene vertical van der Waals heterostructure devices through chemical vapor deposition (CVD) growth, wet transfer method, and dry etching technique. Under 1064 nm laser illumination, we acquire responsivity of as high as 635 A/W and a response time of as short as 19 μs from the as-fabricated device. Moreover, we acquire higher responsivity of 1752 A/W and a shorter response time of 16 μs from the Al2O3-encapsulated device. Our research drives the application of 2D materials in the NIR wavelength range.

High performance near-infrared photodetector based on PbS quantum dots and graphene

The heterojunction photodetector based on zero-dimensional (0-D) PbS quantum dots (QDs) and two-dimensional (2-D) graphene combines the strong light absorption capacity of QDs, adjustable band gap, simple process and other advantages with the higher carrier mobility of graphene, which significantly improves the responsivity and detection rate of the photodetector. In the paper, a photodetector based on the combination of P-InP substrate, graphene and PbS QDs is explored. With the help of Al2O3 passivation of InP substrate, ligand replacement method passivation of PbS QDs, the device shows a unique photoresponse at 808 nm, reaching a detection rate of 145 mAW−1 responsivity under a bias of 1.1 V. The work is expected to provide a strategy for manufacturing and investigating high-performance and low-cost hybrid photodetectors.

High-performance near-infrared photodetectors based on gate-controlled graphene–germanium Schottky junction with split active junction

Abstract The structure of a gate-controlled graphene/germanium hybrid photodetector was optimized by splitting the active region to achieve highly sensitive infrared detection capability. The strengthened internal electric field in the split active junctions enabled efficient collection of photocarriers, resulting in a responsivity of 2.02 A W−1 and a specific detectivity of 5.28 × 1010 Jones with reduced dark current and improved external quantum efficiency; these results are more than doubled compared with the responsivity of 0.85 A W−1 and detectivity of 1.69 × 1010 Jones for a single active junction device. The responsivity of the optimized structure is 1.7, 2.7, and 39 times higher than that of previously reported graphene/Ge with Al2O3 interfacial layer, gate-controlled graphene/Ge, and simple graphene/Ge heterostructure photodetectors, respectively.

High-Performance Near-Infrared Photodetectors Based on the Synergy Effect of Short Wavelength Light Filter and Long Wavelength Response of a Perovskite/Polymer Hybrid Structure.

Near-infrared photodetectors (NIR-PDs) are widely used in communications, biomedical imaging, and national defense. Here we report a new strategy to prepare a short wavelength light filter based NIR-PDs by introducing an interface layer between the perovskite layer and the polymer layer to achieve the selective passage of carriers. Through the synergistic effect of the perovskite and the interface layer, the short wavelength light component in the signal spectrum is effectively filtered out. The organic polymer layer with a bulk heterojunction structure is applied to realize the absorption and conversion of near-infrared light. The prepared device achieves a maximum external quantum efficiency of 83.7% without bias, a high specific detectivity of 1.52 × 1013 Jones, an NIR responsivity of 0.577A/W, and a short response time of 1.73/0.97 μs within the detection range from 770 to 900 nm. All these properties show great advantages compared with other perovskite/polymer hybrid NIR photodetectors that have been reported. This innovative strategy provides a new way to prepare high-performance near-infrared photodetectors.

High-performance near-infrared photodetector based on quasi one-dimensional layered (TaSe4)2I

Infrared photodetectors have attracted great interest due to their wide range of applications. (TaSe4)2I nanowires were prepared by the scotch-tape mechanical exfoliation method, and optoelectronic properties are systematically investigated. The (TaSe4)2I photodetector shows superior performance under the leading role of the photo-bolometric effect. Remarkably, the prefabricated photodetector recorded a superior responsivity of 0.792 A W−1 and a high external quantum efficiency of 100.259% under the condition of near-infrared light. These excellent properties suggest that (TaSe4)2I is a highly competitive candidate for high-performance near-infrared photodetectors.

High-Performance Waveguide-Integrated Bi2O2Se Photodetector for Si Photonic Integrated Circuits.

Due to the excellent electrical and optical properties and their integration capability without lattice matching requirements, low-dimensional materials have received increasing attention in silicon photonic circuits. Bi2O2Se with high carrier mobility, narrow bandgap, and good air stability is very promising for high-performance near-infrared photodetectors. Here, the chemical vapor deposition method is applied to grow Bi2O2Se onto mica, and our developed polycarbonate/polydimethylsiloxane-assisted transfer method enables the clean and intact transfer of Bi2O2Se on top of a silicon waveguide. We demonstrated the Bi2O2Se/Si waveguide integrated photodetector with a small dark current of 72.9 nA, high responsivity of 3.5 A·W-1, fast rise/decay times of 22/78 ns, and low noise-equivalent power of 15.1 pW·Hz-0.5 at an applied voltage of 2 V in the O-band for transverse electric modes. Additionally, a microring resonator is designed for enhancing light-matter interaction, resulting in a wavelength-sensitive photodetector with reduced dark current (15.3 nA at 2 V) and more than a 3-fold enhancement in responsivity at the resonance wavelength, which is suitable for spectrally resolved applications. These results promote the integration of Bi2O2Se with a silicon photonic platform and are expected to accelerate the future use of integrated photodetectors in spectroscopy, sensing, and communication applications.

Towards high-performance near-infrared photodetectors based on SnS nanowires

Compared with bulk structures, semiconductor nanowires exhibit a higher surface-to-volume ratio, as well as unique electrical and optical properties. Due to its narrow band gap, tin (ii) sulfide (SnS) nano wire is a promising candidate for constructing near-infrared (NIR) photodetectors. Uniformly distributed and well-aligned SnS nanowires were grown on a mica substrate by chemical vapor deposition, and NIR photodetectors with Au (Au-device) and Al (Al-device) as the electrode were fabricated and characterized. Compared to the Au-device, the Al-device achieved higher photodetectivity due to reduced dark current. More importantly by incorporating a photosensitive lead phthalocyanine (PbPc) film into the Al-device, both responsivity and detectivity could be apparently improved, especially at weak light intensities. Under a weak light intensity of 0.79 mW/cm 2the photoresponsivity and specific detectivity were improved from and Jones to 0.96 A/W and Jones, respectively.

High-performance near-infrared photodetectors based on C3N quantum dots integrated with single-crystal graphene

Employing C3N QD-integrated single-crystal graphene, photodetectors exhibited a distinct photocurrent response at 1550 nm. The photocurrent map revealed that the fast response derive from C3N QDs that enhanced the local electric field near graphene.

Tin Sulfide Flower-Like Structure as High-Performance Near-Infrared Photodetector

A pH reaction solution adjustment approach is proposed to improve the performance of a flower-like structure-based SnS photodetector. A relatively low-cost chemical bath deposition was adopted to control the growth of a SnS flower-like structure onto a flexible polyethylene terephthalate substrate. The photoresponse characteristics were measured and analyzed using near-infrared (NIR) illumination (850 nm) at various bias voltages. The presented photodetector manifested excellent stability and photoresponse characteristics, including sensitivity (304), the rise time (0.11 s) and the decay time (0.15 s) at 3 V of bias voltage. Based on its good performance, flexibility, low cost, and non-toxic nature, the fabricated flexible photodetector is very promising in the range of NIR.

Graphene/PbS quantum dot hybrid structure for application in near-infrared photodetectors

A graphene-PbS quantum dot (QD) composite for application in high-performance near-infrared (NIR) photodetectors (PDs) is proposed in this study. A single-layer graphene flake and oleic acid-capped PbS QD composite is fabricated through the conventional sonication process, in hexane solution. Field emission scanning electron microscopy images of the graphene-PbS QD composite dispersed on a glass substrate confirm that the composite contains both aggregated graphene flakes and single-layer graphene with wrinkles; Transmission electron microscopy images reveal close packing with uniform size. The increased absorbance and quenched photoluminescence intensity of the graphene-PbS QD composite supports enhanced photoinduced charge transfer between graphene and the PbS QDs. Moreover, the specific Raman mode of the PbS QDs, embedded in the spectrum, is enhanced by combination with graphene, which can be interpreted by SERS as relevant to the photoinduced charge transfer between the Pbs QDs and graphene. For device application, a PD structure comprised by graphene-PbS QDs is fabricated. The photocurrent of the PD is measured using a conventional probe station with a 980-nm NIR laser diode. In the fabricated PD comprising graphene-PbS QDs, five-times higher photocurrent, 22% faster rise time, and 47% faster decay time are observed, compared to that comprising PbS QDs alone. This establishes the potential of the graphene-PbS QD composite for application in ultrathin, flexible, high-performance NIR PDs.

A high-performance near-infrared photodetector based on π-SnS phase

This study presents a novel high-performance, non-toxic and low-cost near-infrared (NIR) photodetector based on a new cubic crystal structure (π-SnS) grown onto silicon wafer substrate by cost-effective and simple chemical bath deposition. The photodetector exhibits excellent photoresponse characteristics under NIR (750 nm) light illumination; sensitivity (3768), detectivity 1.35x1010 Jones, rise time (0.18 s) and decay time (0.16 s) at −5 V bias voltage. Moreover, the photodetector shows excellent reproducibility and stability characteristics. The as-fabricated SnS photodetector is a promising optoelectronic device efficient over NIR range.

Ultrahigh sensitive near-infrared photodetectors based on MoTe2/germanium heterostructure

The efficient near-infrared light detection of the MoTe2/germanium (Ge) heterojunction has been demonstrated. The fabricated MoTe2/Ge van der Waals heterojunction shows excellent photoresponse performances under the illumination of a 915 nm laser. The photoresponsivity and specific detectivity can reach to 12,460 A/W and 3.3 × 1012 Jones, respectively. And the photoresponse time is 5 ms. However, the MoTe2/Ge heterojunction suffers from a large reverse current at dark due to the low barrier between MoTe2 and Ge. Therefore, to reduce the reverse current, an ultrathin GeO2 layer deposited by ozone oxidation has been introduced to the MoTe2/Ge heterojunction. The reverse current of the MoTe2/GeO2/Ge heterojunction at dark was suppressed from 0.44 µA/µm2 to 0.03 nA/µm2, being reduced by more than four orders of magnitude. The MoTe2/Ge heterojunction with the GeO2 layer also exhibits good photoresponse performances, with a high responsivity of 15.6 A/W, short response time of 5 ms, and good specific detectivity of 4.86 × 1011 Jones. These properties suggest that MoTe2/Ge heterostructure is one of the promising structures for the development of high performance near-infrared photodetectors.

Synthesis of Multilayer InSe0.82Te0.18 alloy for high performance near-infrared photodetector

Multilayer InSe has attracted increasing attention due to its excellent electrical and optical properties, making it great potential application in high performance electronic and optoelectronic devices. Alloy engineering is a powerful method to tune electrical and optical properties of semiconductors. However, the alloy engineering has never been applied to multilayer InSe. In this work, for the first time, multilayer InSe0.82Te0.18 alloy photodetector was fabricated and the photodetection performance of multilayer InSe0.82Te0.18 alloy was investigated. Compared to multilayer InSe, the multilayer InSe0.82Te0.18 alloy shows a broader photoresponse region of 400–1100 nm, which is due to its smaller direct bandgap of 1.13 eV. The InSe0.82Te0.18 alloy photodetector exhibits higher photodetection performance than InSe device and the responsivity (R) values are significantly enhanced by 50–300 times, especially in near-infrared (NIR) light region. The R value is 7.1 A/W for 1100 nm light, which surpasses most of multilayer layered semiconductors based NIR photodetector. Moreover, the InSe0.82Te0.18 alloy photodetector owns a good photoresponse stability and relatively fast response time. This work demonstrates that InSe0.82Te0.18 alloy has a great potential application in NIR photodetector.

Two-dimensional phase-engineered 1T′– and 2H–MoTe2-based near-infrared photodetectors with ultra-fast response

Two-dimensional (2D) crystal growth allows wafer-scale van der Waals epitaxial integration of transition metal dichalcogenides (TMDs) semiconductors onto a Si substrate. 2D MoTe2 and WTe2 among TMDs are considered as possible candidates for high-performance near-infrared photodetector, due to its relatively low band gap energy (0.8–1.1 eV). Herein, 2D MoTe2 was selected for the development of high-performance visible–near-infrared (0.5–1.1 μm) photodetectors. Phase-engineered MoTe2 films of four atomic layers were grown by metal–organic chemical vapor deposition on an 8-inch SiO2/Si substrate. 1T′ and 2H phase MoTe2 films were verified by Raman spectra and scanning transmission electron microscopy. A fabricated 2H-MoTe2-based field-effect transistor (FET) was found to have p-type electrical transport with a mobility of 22.8 cm2/V·s—the fastest among all currently reported 2H phase films synthesized by bottom-up methods—and an on/off ratio of 1.3 × 104. Moreover, a photodetector based on the 1T′ phase (semimetal) film exhibited excellent performance, including photoresponsivity as high as 62–109 mA/W at 500–1000 nm—a 900% enhancement over that with a 2H phase (p-type semiconductor) film—and extremely fast response (a rise time of 0.82 μs and a fall time of 7.29 μs at a wavelength of 1000 nm).

Enhanced performance of a graphene/GaAs self-driven near-infrared photodetector with upconversion nanoparticles.

Near-infrared photodetectors (NIRPDs) have attracted great attention because of their wide range of applications in many fields. Herein, a novel self-driven NIRPD at the wavelength of 980 nm is reported based on the graphene/GaAs heterostructure. Extraordinarily, its sensitivity to light illumination (980 nm) is far beyond the absorption limitation of GaAs (874 nm). This means that the photocurrent originates from the separation of photo-induced carriers in graphene, which is caused by the vertically built-in electric field formed through the high quality van der Waals contact between graphene and GaAs. Moreover, after introducing NaYF4:Yb3+/Er3+ upconversion nanoparticles (UCNPs) onto the graphene/GaAs heterojunction, the responsivity increases to be as superior as 5.97 mA W-1 and the corresponding detectivity is 1.1 × 1011 cm Hz0.5 W-1 under self-driven conditions. This dramatic improvement is mainly ascribed to the radiative energy transfer from UCNPs to the graphene/GaAs heterostructure. The high-quality and self-driven UCNPs/graphene/GaAs heterostructure NIRPD holds significant potential for practical application in low-consumption and large-scale optoelectronic devices.