Si Photodetectors Research Articles

Photonic metasurface made of array of lens-like SiGe Mie resonators formed on (100) Si substrate via dewetting

Metasurfaces consisting of arrays of high-index Mie resonators concentrating/redirecting light are important for integrated optics, photodetectors, and solar cells. Herein, we report the optical properties of low-Ge-content SiGe lens-like Mie resonator island arrays fabricated via dewetting during Ge deposition on a Si(100) surface at approximately 900 °C. We observe enhancement of the Si interaction with light owing to the efficient island-induced light concentration in the submicron-depth Si layer, which is mediated by both near-field Mie resonance leaking into the substrate and far-field light focusing. Such metasurfaces can improve the Si photodetector and solar-cell performance.

A monolithically integrated butt-coupled 3D bulk CMOS Si photodetector array with a fiber couplers platform on a single-chip

A linear array of 55 butt-coupled three-dimensional (3D) photodetectors based on a silicon (Si) substrate is presented with a monolithically integrated tapered U-grooves platform for embedding strands of a fiber bundle into a Si chip. This structure enables a direct coupling of the fiber strands with a diameter of Ø30μm to the vertical photoactive areas of a Si detector array one by one. A vertically 3D large photoactive area ∼30μm×40μm+2(30μm×10μm) is formed separated from the n-i-p structure on the top side to achieve a high performance butt-coupled photodetector. The prototype is fabricated by employing 3D CMOS and MEMS technology on a p-type Si wafer. The implementation of 30μm-deep double-trench isolation with the formation of a shallow n+-p junction and SiO2-liner over the trench sidewalls as well as SU-8 filling of the trenches realizes a high efficiency detector isolation and a low dark current of 1.14nA at 2V reverse bias. The maximum photoresponsivities under illumination with 470nm, 525nm, and 631nm LEDs light are observed under the lowest incident light power. A low junction capacitance of ∼30+/−3fF at 2.4V reverse bias is measured at a frequency of 1MHz. Therefore, this approach brings outstanding features for non-telecom and high efficiency remote optical fiber sensor applications at the wavelengths of 470nm, 525nm, and 631nm in high electromagnetic field environments.

(Invited) Detection of Bacterial Fluorescence by the Combination of MEMS Microfluidic Chip and Si Photodetector toward On-Chip Biological Sensing

This work describes the recent researches on bacterial sensing using microelectromechanical systems (MEMS) technology. The fluorescent characteristics of the targeting bacteria, Legionella cells trapped in a bio-MEMS microfluidic chip were studied, showing they emit blue fluorescence when they are forced to stop their motion. The ultraviolet (UV) photoirradiation time dependencies of the fluorescent spectra were compared between Legionella pneumophila (L. pneumophila) and Legionella dumoffii (L. dumoffii). The photocurrent of the fluorescence from L. dumoffii confined in the bio-MEMS microfluidic chip was able to be measured by the Si photodetector with a photogate. These results indicate that the combination of the Si photodetector with bio-MEMS microfluidic chip enables to make bacterial sensors for Legionella on a chip. We are developing a portable small sensor that can detect pathogenic bacteria, Legionella without their cultivation. During the course of the study, we found that the cells emit fluorescence by the ultraviolet (UV) light irradiation just when they are restricted in their motion in microscopic spaces [1]. To confine Legionella cells in such small spaces, we used a glass microbeads suspension and a PDMS-made MEMS microfluidic chip [2]. The fluorescence was observed for L. pneumophila and L. dumoffii confined in the MEMS microfluidic chip using a fluorescence microscope [3]. The fluorescent spectra obtained for both bacteria varied with the UV-photoirradiation time. The spectra of L. pneumophila with beads showed a main and a shoulder peaks at around 450 nm and 520 nm respectively in the initial stages of the UV-photoirradiation with a wavelength of 365 nm. Then the main peak grew with the irradiation time, showing the UV light triggers to produce fluorescent materials. The spectra obtained from L. dumoffii also varied drastically depending on the UV-photoirradiation time. In the initial stages of the photoirradiation, the spectra with multiple peaks appeared and fell off. Subsequently, the spectra with a broad peak gradually grew. This shows that the fluorescent materials which L. dumoffii originally has in their cells as reported in Ref. 4, are photodissociated. After the initial fluorescent materials disappear, the production of the different fluorescent materials begins to occur. Thus, the bacteria might show their own fluorescent characteristics in the motion-restricted situation such as in microfluidic chips. The fluorescent spectral characteristics of Legionella shown above were acquired by the combination of a bulky fluorescence microscope and a spectrometer. However, the integration with the optical sensor on a chip is necessary for easy portable use or in-field use. The successful detection of fluorescence from L. dumoffii is finally described using the microfluidic chip and a fluorescence sensor of Si photodetector with a poly-Si photogate [5]. In the fluorescence detection, the transparent PDMS-made microfluidic chip was set above the detector without any optical filters because the poly-Si photogate prevents the excitation light from entering the sensor by absorbing UV light. This helps the bacterial sensor to be made small. The photocurrent generated by the fluorescence from L. dumoffii cells confined with the beads in the microfluidic chip was able to be observed just after the UV photoirradiation with a wavelength of 365 nm. The time course of the photocurrent intensity was similar to that of fluorescent spectral intensity obtained by the fluorescence microscope mentioned earlier. This indicates the combination of the PDMS-made MEMS microfluidic chip and the Si photodetector enables to make an integrated on-chip bacterial sensor.

(Invited) Detection of Bacterial Fluorescence by the Combination of MEMS Microfluidic Chip and Si Photodetector toward On-Chip Biological Sensing

This work describes the recent researches on bacterial sensing using microelectromechanical systems (MEMS) technology. The fluorescent characteristics for one of the targeting bacteria, Legionella pneumophila (L. pneumophila) cells trapped in a bio-MEMS microfluidic chip were first studied, showing they emit blue fluorescence when they are forced to stop their motion. The ultraviolet (UV) photoirradiation time dependences of fluorescent spectra were further compared between L. pneumophila and L. dumoffii. The photocurrent of fluorescence from L. dumoffii confined in the bio-MEMS microfluidic chip were able to be measured by a photogate-type Si photodetector. These results indicate that the combination of the Si photodetector with bio-MEMS microfluidic chip enables to make bacterial sensors for Legionella on a chip.

Large Area Self-Powered Al-ZnO/(n)Si Hetero-Junction Photodetectors With High Responsivity

Al-ZnO/Si heterojunction-based large area, self-powered, low reverse leakage current, and broadband photodetectors with high responsivity are fabricated using the simple and low temperature process. Different from widely applied (p)Si-based heterojunctions, these devices are (n)Si-based and offer superior performance. With optimized Al–ZnO thickness, excellent light confinement is achieved. An interfacial passivation layer that improves the hetero-interface helps achieved a reverse current density as low as $4.5 \times 10^{-7}$ A/cm $^{-2}$ at −0.5 V for a 4.84 cm2 device, with rectification ratio of $2.7 \times 10^{3}$ at ±0.5 V. In self-powered mode, the photodetector achieved responsivities of 0.292, 0.426, and 0.486 A/W (external quantum efficiency, EQE of 78.7%, 96.1%, and 98.8%) for primary blue (460 nm), green (550 nm), and red (610 nm) light, respectively. The operation of self-powered Al–ZnO/(n)Si photodetectors is demonstrated for the first time with modulated optical signal at circuit level.

Largely Improved Near-Infrared Silicon-Photosensing by the Piezo-Phototronic Effect

Although silicon (Si) devices are the backbone of modern (opto-)electronics, infrared Si-photosensing suffers from low-efficiency due to its limitation in light-absorption. Here, we demonstrate a large improvement in the performance, equivalent to a 366-fold enhancement in photoresponsivity, of a Si-based near-infrared (NIR) photodetector (PD) by introducing the piezo-phototronic effect via a deposited CdS layer. By externally applying a -0.15‰ compressive strain to the heterojunction, carrier-dynamics modulation at the local junction can be induced by the piezoelectric polarization, and the photoresponsivity and detectivity of the PD exhibit an enhancement of two orders of magnitude, with the peak values up to 19.4 A/W and 1.8 × 1012 cm Hz1/2/W, respectively. The obtained maximum responsivity is considerably larger than those of commercial Si and InGaAs PDs in the NIR waveband. Meanwhile, the rise time and fall time are reduced by 84.6% and 76.1% under the external compressive strain. This work provides a cost-effective approach to achieve high-performance NIR photosensing by the piezo-phototronic effect for high-integration Si-based optoelectronic systems.

High-performing MoS2-embedded Si photodetector

Transition metal dichalcogenides (TMDs) are a new class of materials that replace advanced functional materials like graphene, CNT etc., in photovoltaics and sensors. In the present work, the 2-dimensional tri-layer MoS2 is applied for high-performing photodetector. Here, the conventional n-doped p-type Si (n-Si/p-Si) was coated with tri-layer MoS2 film using CVD method. HRTEM reveals the presence of tri-layer with highly ordered lattice planes. Characteristic peaks of Mo and S are obtained in XPS profile. Due to spin-orbit coupling, the 3d band of Mo and 2p band of S are split into two states. Raman spectrum of MoS2 film shows two peaks, corresponding to its in-plane and out-of-plane vibrational modes. The wave number difference between these modes is measured as 22.97cm−1, which ensures that there are three layers in MoS2 film. The splitting of valence band generates multiple excitons which are marked as A and B in the absorption profile. The excitonic transition corresponds to the direct band gap of MoS2 (ie., 1.9eV). The prepared MoS2/n-Si/p-Si photodetector includes two rectifying junctions with considerable built-in potentials. A high rectification ratio was measured as 51.37 to ensure the quality junction formation. The photoresponse ratio of the MoS2/n-Si/p-Si photodetector was obtained as 58.74 to confirm the quality junction formation between MoS2 and Si with high detectivity of 5.42 × 1014 Jones. Moreover, the extremely fast rise and fall times of 33 µs and 30 µs were achieved without any external bias application. The functional use of MoS2 window design would provide the high potential for the enhanced photoelectric devices, such as photodetectors and solar cells.

Characteristics of stacked multi-slot ring resonator sensors

PurposeThis paper aims to develop ring resonator type optical sensors for high-sensitive detection of biomaterials and a solution concentration surrounding sensor devices. The sensing characteristics of a proposed device are investigated.Design/methodology/approachThe proposed device structure is multi-slot ring resonator where the horizontal slots are arranged in vertical direction called as stacked multi-slot ring resonator. The ring resonator consists of silicon nitride because of several advantages such as easy integration of Si photo-detectors. A high sensitivity is expected in this structure because the slot height is precisely controlled by the thickness of stacked silicon nitride and etched silicon oxide layers. Sensing characteristics are evaluated from the simulated effective refractive index using the finite element method and sucrose solution sensing is confirmed using polydimethylsiloxane fluid channel.FindingsIn the simulation for the solution concentration sensor, the detection sensitivity is enhanced with increasing the slot height and the number of slots. On the other hand, for the biomaterial sensor such as the adsorbed antigen-antibody reaction, the sensitivity increases with decreasing the slot height. In this case, more than four times higher sensitivity is expected compared with the slot ring resonator sensor with vertical single slot and 0.1-0.2 μm slot width.Originality/valueThis paper presents an improved new structure of ring resonator type sensors and its optimum design parameters. The sensing characteristics are evaluated, and, for the biomaterial sensor, the sensitivity is high in comparison to the previous slot ring resonator.

Refractive index sensing in the visible/NIR spectrum using silicon nanopillar arrays.

Si nanopillar (NP) arrays are investigated as refractive index sensors in the visible/NIR wavelength range, suitable for Si photodetector responsivity. The NP arrays are fabricated by nanoimprint lithography and dry etching, and coated with thin dielectric layers. The reflectivity peaks obtained by finite-difference time-domain (FDTD) simulations show a linear shift with coating layer thickness. At 730 nm wavelength, sensitivities of ~0.3 and ~0.9 nm/nm of SiO2 and Si3N4, respectively, are obtained; and the optical thicknesses of the deposited surface coatings are determined by comparing the experimental and simulated data. The results show that NP arrays can be used for sensing surface bio-layers. The proposed method could be useful to determine the optical thickness of surface coatings, conformal and non-conformal, in NP-based optical devices.

Solution-processed, hybrid 2D/3D MoS2/Si heterostructures with superior junction characteristics

We report a theoretical and experimental investigation of the hybrid heterostructure interfaces between atomically thin MoS2 nanocrystals (NCs) on Si platform for their potential applications towards next-generation electrical and optical devices. Mie theory-based numerical analysis and COMSOL simulations based on the finite element method have been utilized to study the optical absorption characteristics and light–matter interactions in variable-sized MoS2 NCs. The size-dependent absorption characteristics and the enhancement of electric field of the heterojunction in the UV-visible spectral range agree well with the experimental results. A lithography-free, wafer-scale, 2D material on a 3D substrate hybrid vertical heterostructure has been fabricated using colloidal n-MoS2 NCs on p-Si. The fabricated p-n heterojunction exhibited excellent junction characteristics with a high rectification ratio suitable for voltage clipper and rectifier applications. The current–voltage characteristics of the devices under illumination have been performed in the temperature range of 10–300 K. The device exhibits a high photo-to-dark current ratio of ∼3 × 103 and a responsivity comparable to a commercial Si photodetector. The excellent heterojunction characteristics demonstrate the great potential of MoS2 NC-based hybrid electronic and optoelectronic devices in the near future.

Flexible silicon sensors for diffuse reflectance spectroscopy of tissue.

Diffuse reflectance spectroscopy (DRS) is being used in exploratory clinical applications such as cancer margin assessment on excised tissue. However, when interrogating nonplanar tissue anomalies can arise from non-uniform pressure. Herein is reported the design, fabrication, and test of flexible, thin film silicon photodetectors (PDs) bonded to a flexible substrate designed for use in conformal DRS. The PDs have dark currents and responsivities comparable to conventional Si PDs, and were characterized while flat and while flexed at multiple radii of curvature using liquid phantoms mimicking adipose and malignant breast tissue. The DRS and nearest neighbor crosstalk results were compared with Monte Carlo simulations, showing good agreement between simulation and experiment.

Influence of High Dose Gamma Irradiation on Electrical Characteristics of Si Photo Detectors

The radiation response of Si photo detectors has been studied through Current voltage (I-V) and Capacitance Voltage (C-V) measurements for accumulated high doses of Co-60 gamma rays in the wide range of 1 Mrad to 100 Mrad. The key electrical parameters such as ideality factor (n), series resistance (RS) and reverse leakage current (IR) has been extracted from I-V characteristics. The acceptor concentration (NA) was extracted from C-V characteristics. The detectors exhibited degradation in the values of electrical parameters up to 60 Mrad, further at higher doses improvement in their values is noticed. The lattice defects introduced by gamma rays may have significantly contributed to the deterioration of device parameters at initial doses, whereas the partial recovery at higher does is attributed to annealing effect of gamma rays due to its electronic energy loss (Se) component.

Wettability effects of graphene oxide aqueous solution in photodetectors based on graphene oxide/silicon heterojunctions via ultraviolet ozone treatment

We report the wettability effects of graphene oxide (GO) aqueous solution on the electrical and photoresponse properties of GO-silicon (Si) photodetectors via ultraviolet ozone (UVO) treatment. GO-Si vertical heterojunctions were fabricated using a spray-coating method. In the GO/p-Si heterojunctions without UVO treatment (GO/p-Si), an island-like assembly of GO sheets was formed, indicating that a GO stacking structure may have an island shape on the substrate due to partial surface coverage. In contrast, for those with UVO treatment (GO/UVO-p-Si), a relatively more close-packed GO deposition may occur due to the more hydrophilic property of the substrate surface, leading to the full surface coverage of the p-Si surface. Photodetectors based on GO/p-Si and GO/UVO-p-Si heterojunctions exhibit distinct electrical and photoresponse properties. The GO/UVO-p-Si-based devices showed a higher photo-to-dark current ratio, higher turn-on voltage, and lower ideality factor compared to the GO/p-Si-based devices. The transport mechanism in the photodetectors can be explained in terms of space-charge-limited conduction and the tunneling of charge carriers through the GO layer.

Integrated High-Performance Infrared Phototransistor Arrays Composed of Nonlayered PbS-MoS2 Heterostructures with Edge Contacts.

Molybdenum disulfide (MoS2) has attracted a great deal of attention in optoelectronic applications due to its high mobility, low off-state current and high on/off ratio. However, its intrinsic large bandgap limits its application in infrared detection. Here, we have developed a high-performance infrared photodetector by integrating nonlayered PbS and layered MoS2 nanostructures via van der Waals epitaxy. Density functional theory (DFT) calculations indicate that PbS nanoplates are in contact with MoS2 edges through strong chemical hybridization, which is expected to offer a fast transmission path for carriers that enhances the response speed. The phototransistor exhibits a fast response (τrising = τdecay = 7.8 ms) as well as high photoresponsivity (4.5 × 104 A·W-1) and Ilight/Idark (1.3 × 102) in the near-infrared spectral region at room temperature. In particular, the detectivity (D*) is as high as 3 × 1013 Jones, which is even better than that of commercial Si and InGaAs photodetectors. Furthermore, by controlling the growth and microfabrication patterning, periodic device arrays of PbS-MoS2 that are capable of infrared detection are achieved on Si/SiO2 substrates. Our work provides a possible method for the integration of photodetector arrays on Si-based electronic devices and lays a solid foundation for the practical applications of MoS2-based devices in the future.

Silicon photodetectors with triple p–n junctions in CMOS technology at 650‐ and 850‐nm wavelengths

A triple p–n junction Si photodetector using 0.25-μm standard CMOS process at 650- and 850-nm wavelengths is presented and investigated. Triple p–n junctions are formed vertically by n+-implant/p-well (N+/HVPW), p-well/n+-buried layer (HVPW/NBL), and n+-buried layer/p-substrate (NBL/P-sub) junctions to attain a wavelength-dependent response. The responsivity and pulse response were characterised in different bias schemes. Measured photocurrents from HVPW/NBL and NBL/P-sub junctions under reverse biasing and a floating electrode on N+-HVPW showed the smallest FWHM values. The −3 dB bandwidth of 1.9 GHz converted from pulse measurement is the highest result ever reported in 654-nm wavelength using standard CMOS technology. The proposed triple p–n junction Si photodetector with bias schemes shows combined excellent performance in 650- and 850-nm wavelengths.

Stable, Fast UV-Vis-NIR Photodetector with Excellent Responsivity, Detectivity, and Sensitivity Based on α-In2Te3 Films with a Direct Bandgap.

Photoelectric conversion is of great importance to extensive applications. However, thus far, photodetectors integrated with high responsivity, excellent detectivity, large phototo-dark current ratio, fast response speed, broad spectral range, and good stability are rarely achieved. Herein, we deposited large-scale and high-quality polycrystalline indium sesquitelluride (α-In2Te3) films via pulsed-laser deposition. Then, we demonstrated that the photodetectors made of the prepared α-In2Te3 films possess stable photoswitching behavior from 370 to 1064 nm and short response time better than ca. 15 ms. At a source-drain voltage of 5 V, the device achieves a high responsivity of 44 A/W, along with an outstanding detectivity of 6 × 10(12) cm H(1/2) W(-1) and an excellent sensitivity of 2.5 × 10(5) cm(2)/W. All of these figures-of-merit are the best among those of the reported α-In2Te3 photodetectors. In fact, they are comparable to the state-of-the-art commercial Si and Ge photodetectors. For the first time, we established the theoretical evidence that α-In2Te3 possesses a direct bandgap structure, which reasonably accounts for the superior photodetection performances above. Importantly, the device exhibits a good stability against the multiple photoswitching operation and ambient environment, along with no obvious voltage-scan hysteresis. These excellent figures-of-merit, together with the broad spectral range and good stability, underscore α-In2Te3 as a promising candidate material for next-generation photodetection.

Design and construction of ultra-thin MoSe2 nanosheet-based heterojunction for high-speed and low-noise photodetection

Advances in the photocurrent conversion of two-dimensional (2D) transition metal dichalcogenides have enabled the realization and application of ultrasensitive and broad-spectral photodetectors. The requirements of previous devices constantly drive for complex technological implementation, resulting in limits in scale and complexity. Furthermore, the development of large-area and low-cost photodetectors would be beneficial for applications. Therefore, we demonstrate a novel design of a heterojunction photodetector based on solution-processed ultrathin MoSe2 nanosheets to satisfy the requirements of its application. The photodetector exhibits a high sensitivity to visible–near infrared light, with a linear dynamic range over 124 decibels (dB), a detectivity of ~1.2 × 1012 Jones, and noise current approaching 0.1 pA·Hz–1/2 at zero bias. Significantly, the device shows an ultra-high response speed up to 30 ns with a 3-dB predicted bandwidth over 32 MHz, which is far better than that of most of the 2D nanostructured and solution-processable photodetectors reported thus far and is comparable to that of commercial Si photodetectors. Combining our results with material-preparation methods, together with the methodology of device fabrication presented herein, can provide a pathway for the large-area integration of low-cost, high-speed photodetectors.

Increased spectral sensitivity of Si photodetector by surface plasmon effect of Ag nanowires

Highly-sensitive Si photodetectors were prepared by using Ag nanowires (AgNWs). A transparent indium-tin-oxide (ITO) coating was coated on a Si substrate followed by spin-coating of AgNWs-containing solution. AgNWs having average length of 5–20μm with a diameter of about 40–60nm were observed in FESEM images. The haze effect of AgNWs was totally avoided because of the optimum value of diameter. The transmittance of above 85% was shown by AgNWs over a broad spectral range due to surface plasmon resonance effect. The AgNW-coated device showed an excellent rectifying ratio of 288. Under light illumination, AgNWs-coated device exhibited a significant photoresponse ratio of 5373. This advanced feature of AgNWs-templated method would be applied in broadband wavelength photodetection devices.

In Situ Electrical Characteristics of 150 MeV Ag9+ Ion Beam Induced Damage in Si Photo Detector

The effect of 150 MeV Ag9+ ion irradiation on electrical characteristics of Si photo detectors has been analyzed through in-situ Current voltage (I-V) and Capacitance voltage (C-V) measurements. Ideality factor (n), series resistance (Rs) and reverse leakage current (IR) are extracted from I-V characteristics. The value of n for pristine detector is found to be 1.24 and it has increased gradually along with the fluence. The value of IR for pristine is found to be 4.97 × 10−8 A and it increases to about three orders of magnitude at the fluence of 1 × 1013 ions/cm2 and further there is no observable change. Also, C-V characteristics exhibit considerable degradation. The value of capacitance decreased from 1.13 ×10−8 F to 3.97 × 10−10 F and also carrier concentration (NA) undergoes slight decrease with the increase in fluence. The 150 MeV Ag9+ ion induced displacements, vacancies in the bulk region mainly attribute to the observed degradation in the electrical characteristics. The ionization and displacement damage profiles were estimated from SRIM/TRIM (Stopping power and Range of Ion in Matter/Transport and Range of Ion in Matter) simulation codes. The observed degradations are explained in terms of TID (total ionization dose) and Dd (displacement damage dose).

Ultrasensitive PbS quantum-dot-sensitized InGaZnO hybrid photoinverter for near-infrared detection and imaging with high photogain

Lead sulfide (PbS) quantum dots (QDs) have great potential in optoelectronic applications because of their desirable characteristics as a light absorber for near-infrared (NIR) photodetection. However, most PbS-based NIR photodetectors are two-terminal devices, which require an integrated pixel circuit to be practical photosensors. Here we report on PbS QD/indium gallium zinc oxide (InGaZnO, IGZO) metal oxide semiconductor hybrid phototransistors with a photodetection capability between 700 and 1400 nm, a range that neither conventional Si nor InGaAs photodetectors can cover. The new hybrid phototransistor exhibits excellent photoresponsivity of over 106 A W−1 and a specific detectivity in the order of 1013 Jones for NIR (1000 nm) light. Furthermore, we demonstrate an NIR (1300 nm) imager using photogating inverter pixels based on PbS/IGZO phototransistors at an imaging frequency of 1 Hz with a high output voltage photogain of ~4.9 V (~99%). To the best of our knowledge, this report demonstrates the first QD/metal oxide hybrid phototransistor-based flat panel NIR imager. Our hybrid approach using QD/metal oxide paves the way for the development of gate-tunable and highly sensitive flat panel NIR sensors/imagers that can be easily integrated. A hybrid near-infrared photoinverter based on lead sulphide quantum (PbS) dots and InGaZnO that exhibits a high photogain has been made. PbS quantum dots have promising properties for near-infrared detection, but two-terminal devices based on them require an integrated pixel circuit. Now, Do Kyung Hwang at Korea University of Science and Technology and co-workers have demonstrated a hybrid near-infrared detector that employs PbS quantum dots to sensitize InGaZnO. The detector covers a wavelength range of 700–1,400 nanometres, which is not covered by conventional photodetectors. It also exhibits an excellent photoresponsivity of over 106 amperes per watt. The researchers consider that this approach will open up the way to develop highly sensitive, flat-panel near-infrared sensors and imagers that are both gate tunable and readily integrable. We propose hybrid approach of two classes of PbS QD as NIR light absorber and IGZO as the photogenerated charges acceptor/transport semiconductor to create phototransistor for near infrared (NIR) detection/imaging. Such hybrid phototransistor shows photodetection capability between 700 and 1400 nm. We demonstrate a NIR (1300 nm) imager using photogating inverter pixel based on PbS/IGZO hybrid phototransistor.