Ultrasensitive Photodetectors Research Articles

Ultrasensitive and broad-spectrum polarization sensitive photodetector based on individual Bi2Te0.6S2.4 nanobelt

Polarimetric photodetectors with broadband and fast response have important applications in the military and civilian fields. Alloying of semiconductors is a good strategy to regulate its electronic band structure which broadens the photoresponse range of the corresponding optoelectronic devices. In this work, we designed and grew the high-quality Bi2Te0.6S2.4 alloy via controllable chemical vapor transport. The as-prepared Bi2Te0.6S2.4 nanobelts were designed to work as the active layer in photodetectors. The individual Bi2Te0.6S2.4 nanobelt based photodetector exhibits excellent photoresponse properties in a broadband range from solar-blind ultraviolet-C (254 nm) to near-infrared (1064 nm) with a good responsivity of 340 mA/W, a specific detectivity of 2.3 × 109 Jones, and extremely low dark current (1.1 pA). The photodetectors also exhibit a fast response speed of about 1 μs which comes from the direct transition of carriers in Bi2Te0.6S2.4 confirmed by the Ohmic contact between Bi2Te0.6S2.4 and electrodes. Furthermore, it is worth noting that the Bi2Te0.6S2.4 nanobelts have high polarization sensitivity in the broadband ranges from 266 to 1064 nm with the maximum dichroic ratio of 2.94 at 808 nm. Our results provide a simple Bi based semiconductor system for high performance multifunctional optoelectronics and electronics compared with conventional Bi based chalcogenides.

(Invited) Broadband and Broad Angle Enhanced Light Absorption in MoS2 based Hetero Plasmonic Structure

Solar cells, photovoltaic devices and optoelectronic elements needs enhanced light absorption with a wide range of incident angle for better and efficient design. Two-dimensional (2D) materials have exceled in all areas including electrical applications, optical modulations, mechanical as well as chemical implementations due to their direct bandgap and high optical absorption nature[1]. Photon irradiation allows to generate electron-hole pairs in a direct bandgap material such as TMDCs which makes them potential candidates for large amount of light to be trapped. Different structures have been studied to achieve high optical absorption [2][3]. Although one dimensional photonic crystal(1DPC) and defective PC has good optical absorption with wide range and angle [4],[2] number of layers and complexity in structure has made it difficult to be fabricated. MoS2 monolayer structure based on cover spacer, plasmonic and dual substrate layer (SiO2(50nm)/Si ) has also increased optical absorption range and broad angle [5] but TMDC based heterostructures with spacer has improved absorption comparing to previous structures without metallic layer [6]. In this paper, we proposed a dual TMDC-spacer based plasmonic structure with dual substrate for wide and broad range and angle of near perfect optical absorption.The structure considered here is an air/MoS2/Spacer1/MoS2/Spacer2/plasmonic/dual substrate with 0.665nm, 70nm and 50nm layer of MoS2, Au as plasmonic layer and SiO2 as part of dual layer with Si as lossless substate. (Figure 1) For spacers SiO2 and TiO2 are taken with optimized value (figure 2) of 92 and 68nm for enhanced absorption. The transfer matrix of the constituted layer for either transverse electric (TE) or transverse magnetic (TM) polarization was determined using the transfer matrix method (TMM). Both in TE and TM mode, the ~30 and ~40% of enhanced light absorption are observed in proposed structure compared to hetero and mono layer structure (figure 3) with impact of metallic and spacer layer. In case of incident angle, both at resonance frequency of MoS2 and within visible range, broad angle range (00-400 for TE and 00-800 for TM) is observed with wider wavelength. (Figure 4 and figure 5). Impact of various metallic layer on the proposed structure is also observed (Figure 6). Structure with VO2 as plasmonic layer [7] has around ~95% of peak absorption (400nm-550nm) and wide incident angle (00-850) irrespective of polarizations with lieu of spacer hetero-TMDC-stack (Figure 7). Due to multiple layers of structures, collective surface plasmon polaritons (SPP) has an enhanced light absorption within the heterostructure and enhanced electric field distribution of the structure is observed (Figure 8).Table I lists some comparison among various structures and parameters indicates that proposed dual spacer -TMDC based plasmonic heterostructure has wide visible range of wavelength (400-550 nm) with broad angle (00-850) light absorption with both polarizations compare to other counterparts.In this work an enhanced range in both wavelength and incident angle of visible optical absorption is observed in both polarization with plasmonic dual heterostructure is observed and compared with other structures. Such structures are useful for photodetectors and solar cells for maximum absorptions.[1] Lopez-Sanchez O, Lembke D, Kayci M, Radenovic A and Kis A 2013 Ultrasensitive photodetectors based on monolayer MoS 2 Nat. Nanotechnol. 8 497–501[2] Ansari N and Mohebbi E 2018 Broadband and high absorption in Fibonacci photonic crystal including MoS2 monolayer in the visible range J. Phys. D. Appl. Phys. 51 149–52[3] Ansari N and Ghorbani F 2018 Light absorption optimization in two-dimensional transition metal dichalcogenide van der Waals heterostructures J. Opt. Soc. Am. B 35 1179[4] Ansari N and Mohebbi E 2016 Increasing optical absorption in one-dimensional photonic crystals including MoS2 monolayer for photovoltaics applications Opt. Mater. (Amst). 62 152–8[5] Ansari N, Mohebbi E and Gholami F 2020 Nearly perfect and broadband optical absorption by TMDCs in cover/TMDC/spacer/Au/substrate multilayers Appl. Phys. B Lasers Opt. 126 1–6[6] Ansari N, Goudarzi B and Mohebbi E 2021 Design of narrowband or broadband absorber by heterostructures including TMDCs and spacers Opt. Laser Technol. 138 106771[7] Das H R and Arya S C 2021 Performance improvement of VO2 and ITO based plasmonic electro-absorption modulators at 1550 nm application wavelength Opt. Commun. 479 Figure 1

Ultraflexible and Ultrasensitive Near‐Infrared Organic Phototransistors for Hemispherical Biomimetic Eyes

AbstractThe diverse biological eyes vision systems found in nature can provide attractive design inspiration for near‐infrared (NIR) imaging devices. Outstanding features of the retina are its concave hemisphere geometry and high‐sensitivity image acquisition, which simplify the optical complexity of the eye and improve the imaging quality of visual perception. However, developing high‐performance NIR biomimetic imaging systems with these characteristics is extremely challenging due to the limitations of their hemisphere‐like structures, constituent materials, and conventional imaging modules. Here, a hemispherical biomimetic eyes imaging system based on ultraflexible all‐polymer heterojunction NIR phototransistors is presented. The device features a self‐supporting ultrathin (≈659 nm) NIR imaging structure that can maintain stable photoelectric performance while adhering to the human body or arbitrary‐shaped objects and have extraordinary photosensitivity (≈106) under dim light conditions (0.038 mW cm−2, 808 nm). Based on the versatile NIR device array, hemispherical ultrasensitive NIR biomimetic eyes are successfully achieved and higher‐resolution imaging is realized. Results demonstrated in this work provide a new strategy for constructing ultraflexible and ultrasensitive NIR photodetectors, showing remarkable application potential in next‐generation visual prosthetics and intelligent bioimaging systems.

Solution Processed Photodetectors with PVK-WS2 Nanotube/Nanofullerene Organic-Inorganic Hybrid Films.

Organic-inorganic hybrid photodetectors have attracted increased interest due to their exceptional properties, such as flexibility, transparency, and low cost for many promising applications. Low-dimensional tungsten disulfide (WS2) nanostructures have outstanding electrical and optical properties, making them ideal candidates for ultrasensitive photodetector devices. In this paper, photodetectors were fabricated with hybrid thin films containing two different WS2 nanomaterials, one-dimensional (1D) WS2 nanotubes (WS2-NTs) and a zero-dimensional (0D) WS2 nanofullerene (WS2-FLs) hybrid with poly(N-vinyl carbazole) (PVK). The electrical responses of the devices under visible-light illuminations were studied. The photodetector devices with 0D WS2-FLs/PVK hybrid thin films have relatively higher sensitivity and stable voltage responses to visible light. Besides, the hybrid film shows a strong surface-enhanced Raman effect (SERS). These materials and new strategies enable the creation of a new class of processed photodetectors for practical applications.

Ultrasensitive and broadband polarization-sensitive topological insulator photodetector induced by element substitution

Topological insulators are considered as one of the preferred materials for high-performance optoelectronic devices due to their small bulk bandgaps and ultra-high carrier mobility. However, the existence of their unique Dirac like surface states makes the corresponding optoelectronic devices to have high dark current, and the logic circuit cannot be turned off effectively. Opening the surface state gap by element doping is an effective means to achieve high performance of devices. Here, we design and prepare single crystal Bi2Se2.15S0.85 nanowires by a facile iodine-assisted chemical vapor transport method and a fabricated individual Bi2Se2.15S0.85 nanowire based photodetector. The devices exhibit remarkable photoresponse over the broadband wavelength ranging from ultraviolet C (275 nm) to near-infrared (1310 nm) with the low dark current of 10−12 A. They show superior optoelectrical properties with an ultrafast response speed of 170 ns, detectivity of 9.35 × 1011 Jones, a competitive responsivity of 1.31 A/W, and superb stability to keep great photoresponse for at least one year, which are superior to the reported photodetectors. Additionally, benefiting from the anisotropic crystal structure of Bi2Se2.15S0.85, the devices also display good polarization detection performance in a wide spectral range from 266 nm to 1064 nm with a dichroic ratio of 1.81 at 360 nm.

Single-Crystalline Perovskite p-n Junction Nanowire Arrays for Ultrasensitive Photodetection.

Highly sensitive photodetectors play significant roles in modern optoelectronic integrated circuits. Constructing p-n junctions has been proven to be a particularly powerful approach to realizing sensitive photodetection due to their efficient carrier separation. Recently, p-n-junction photodetectors based on organic-inorganic hybrid perovskites, which combine favorable optoelectronic performance with facile processability, hold great potential in practical applications. So far, these devices have generally been made of polycrystalline films, which exhibit poor carrier-transport efficiency, impeding the further improvement of their photoresponsivities. Here, a type of ultrasensitive photodetector based on single-crystalline perovskite p-n-junction nanowire arrays is demonstrated. The single-crystalline perovskite p-n-junction nanowire arrays not only possess high crystallinity that enables efficient carrier transport but also form a built-in electric field facilitating effective carrier separation. As a result, the devices show excellent photosensitivity over a wide spectral range from 405 to 635nm with an outstanding responsivity of 2.65×102 AW-1 at 532nm. These results will provide new insights into the design and construction of high-performance photodetectors for practical optoelectronic applications.

Tunable high-quality-factor absorption in a graphene monolayer based on quasi-bound states in the continuum.

A tunable graphene absorber, composed of a graphene monolayer and a substrate spaced by a subwavelength dielectric grating, is proposed and investigated. Strong light absorption in the graphene monolayer is achieved due to the formation of embedded optical quasi-bound states in the continuum in the subwavelength dielectric grating. The physical origin of the absorption with high quality factor is examined by investigating the electromagnetic field distributions. Interestingly, we found that the proposed absorber possesses high spatial directivity and performs similar to an antenna, which can also be utilized as a thermal emitter. Besides, the spectral position of the absorption peak can not only be adjusted by changing the geometrical parameters of dielectric grating, but it is also tunable by a small change in the Fermi level of the graphene sheet. This novel scheme to tune the absorption of graphene may find potential applications for the realization of ultrasensitive biosensors, photodetectors, and narrow-band filters.

Ultrasensitive V doped WO3 1D nanorods heterojunction photodetector with pronounced photosensing activities

In this study, vanadium-doped tungsten oxide (V-WO3) nanorods heterostructures are designed by a simple, facile, and eco-friendly hydrothermal method and applied for photo-sensing activities. Physical characterization results indicate the phase purity, crystalline nature, tuneable energy bandgap, higher surface area, and successful formation of V doped WO3 nanorods. Optoelectronic properties reveal pronounced photo-sensing capabilities of the designed material demonstrating efficient charge transfer. The photocurrent density is enhanced with laser power. Large values of open-circuit voltage (Voc) and short-circuit current (Isc) in the range of 0.91 V and 28 mA/cm2, respectively, are obtained at 56 mW/cm2 power. The Isc is enhanced considerably as a function of power intensity of laser due to the formation of large number of photo-induced electron-hole pairs and large value of built-in potential. Furthermore, to estimate the response time of the device, the measured temporal photoresponse is 4500 A/W, several-fold higher than previously reported materials, associated with suppression in the dark current. In addition, the detectivity of V doped WO3 NRs photodetector lies in the range of 5.15×1011 Jones and the calculated value of detectivity and EQE is ~70%. These results are interesting and provide a roadmap to design ultrasensitive photodetectors.

Ultrasensitive p-n junction UV-C photodetector based on p-Si/β-Ga2O3 nanowire arrays

Ultrasensitive UV-C photodetector (PD) based on β-Ga2O3 nanowires (NWs) were fabricated on p-type Si substrate using glancing angle deposition technique inside RF/DC sputtering chamber. The formation of well-aligned NWs with an average length of ~ 270 nm was confirmed with the help of field emission scanning electron microscope (FE-SEM) images. Also, the fabricated β-Ga2O3 NWs array were polycrystalline in nature. Furthermore, a good photo absorption and photoemission were obtained from the fabricated sample. The PD fabricated using β-Ga2O3 NW operated in the UV-C region (275 nm) with a recorded responsivity of 31.71 A/W, detectivity of 1.37×1012 Jones and an NEP of 2.44×10−12 W at + 5 V. Additionally, the PD was able to respond at a very low power light of 6.37 µW/cm2. The transient response of the fabricated device shows a rise time and fall time of 0.18 s and 0.25 s respectively. The high performance was attributed to the strong p-n junction which could separate the photogenerated carriers efficiently.

Ultra-sensitive polarization-resolved black phosphorus homojunction photodetector defined by ferroelectric domains

With the further miniaturization and integration of multi-dimensional optical information detection devices, polarization-sensitive photodetectors based on anisotropic low-dimension materials have attractive potential applications. However, the performance of these devices is restricted by intrinsic property of materials leading to a small polarization ratio of the detectors. Here, we construct a black phosphorus (BP) homojunction photodetector defined by ferroelectric domains with ultra-sensitive polarization photoresponse. With the modulation of ferroelectric field, the BP exhibits anisotropic dispersion changes, leading an increased photothermalelectric (PTE) current in the armchair (AC) direction. Moreover, the PN junction can promote the PTE current and accelerate carrier separation. As a result, the BP photodetector demonstrates an ultrahigh polarization ratio (PR) of 288 at 1450 nm incident light, a large photoresponsivity of 1.06 A/W, and a high detectivity of 1.27 × 1011 cmHz1/2W−1 at room temperature. This work reveals the great potential of BP in future polarized light detection.

Outage probability analysis of a vertical underwater wireless optical link subject to oceanic turbulence and pointing errors

The reliability of an underwater wireless optical communication (UWOC) network is seriously impacted by beam misalignment between transmitters (Txs) and receivers (Rxs). Also, the performance of UWOC systems can be affected by oceanic turbulence-induced fading due to fluctuations in the water refractive index as a result of variations in the pressure, water temperature, and salinity. In this work, we investigate the performance analysis of a vertical UWOC link subject to oceanic turbulence and pointing errors and further investigate the appropriate selection of link parameters to optimize link performance. This study is based on an accurate mathematical framework for link modeling while taking into account realistic Tx/Rx and channel parameters under different turbulence and beam misalignment conditions. We provide an analytical expression for calculating the link outage probability, whose accuracy is validated through numerical simulations. Last, the necessity of optimal Tx/Rx parameter selection to minimize the link outage is demonstrated. A laser beam is considered at the Tx, as well as an ultra-sensitive photodetector (silicon photo-multiplier) at the Rx to enable working at relatively long link ranges. The presented results give valuable insight into the practical aspects of deployment of UWOC networks.

Solution-Processed Ternary Perovskite-Organic Broadband Photodetectors with Ultrahigh Detectivity.

Room temperature operated, solution-processed ultrasensitive broadband photodetectors are widely used in various industrial companies in the scientific and medical sectors. Herein, we report solution-processed ultrahigh detectivity broadband photodetectors based on the ternary perovskite-organic composites. To ensure the photodetector based on perovskites has a photoresponse from the ultraviolet-visible to the near-infrared (NIR) region, low optical gap n-type conjugated organic molecules are incorporated with the three-dimensional (3D) perovskites mixed with the two-dimensional (2D) perovskites to form the ternary perovskite-organic composites, which possess an extended spectral response up to the NIR region and superior film characteristics compared to the 2D-3D mixed perovskite composites. Moreover, the photodetectors based on the ternary perovskite-organic composites exhibit enhanced photocurrent and suppressed dark current compared to those based on the 2D/3D mixed perovskite composites. As a result, at room temperature, the photodetectors based on the ternary perovskite-organic composites exhibit a spectral response from 375 to 1000 nm, whereas the photodetectors based on the 2D-3D mixed perovskite composites exhibit a spectral response from 375 to 800 nm. Furthermore, the photodetectors based on the ternary perovskite-organic composites have a photodetectivity over 1015 cm Hz1/2 W-1 (Jones) in the ultraviolet-visible region and over 1013 Jones in the NIR region, a linear dynamic range over 110 dB, and a fast response time. All these results demonstrate that we developed a facile way to realize uncooled solution-processed ultrahigh detectivity broadband photodetectors based on the ternary perovskite-organic composites.

Ultrasensitive Photodetectors Based on Strongly Interacted Layered-Perovskite Nanowires.

Metal-halide layered perovskites, self-assembled quantum wells with alternating insulating interlayer organic cations, and conductive perovskite layers boost the incorporation of multiple functionalities into a single-phase material. Optoelectronic performances in layered perovskites are more sensitive to crystallinity than their 3D counterparts due to the traps and insulating barriers introduced by interlayer cations. Here, we combine the capillary-bridge lithography method for the fabrication of single-crystalline nanowire arrays with strongly interacted layered perovskites for the enhancement of crystallinity and crystallographic orientation purity. Due to regulated nucleation and growth of layered perovskites in capillary bridges and the sulfur-sulfur interaction between interlayer cations, nanowires with pure (101) orientation are realized for underpinning insulating crystal interiors and photoconductive layer edges. Based on these nanowires, ultrasensitive photodetectors are reached with an ultralow dark current of below 10-12 A, an average responsivity of 7.3 × 103 A W-1, an average specific detectivity of 3.9 × 1015 Jones, and a 3 dB bandwidth of 10.3 kHz.

Structural engineering of single-crystal-like perovskite nanocrystals for ultrasensitive photodetector applications

We report the synthesis method of ultralong one-dimensional (1D) inorganic perovskite nanorods with single-crystal-like molecular orientation for photodetector applications.

Schottky-Contacted WSe2 Hot-Electron Photodetectors with Fast Response and High Sensitivity

Utilizing the short lifetime of hot electrons, ultrasensitive hot-electron photodetectors with fast response speed can be developed that have the potential to carve a niche among the photoconductive devices. Herein, high-performance WSe2 photodetectors are fabricated based on hot-electron transportation, in which an ultrathin Al2O3 layer enables screening of high-energy hot electrons and promises ultrasensitive response to incident light, and the built-in electric field in Schottky junctions separates the photoinduced carriers for fast transient recovery. The hot-electron photodetectors demonstrated a high rectification ratio of 107 and an extremely low dark current of 1 pA/μm with a high Ilight/Idark ratio of 1.8 × 106. Moreover, a high responsivity of 3.69 A/W and detectivity of 2.39 × 1013 Jones at an incident light power of 5.0 μW/cm2 are simultaneously achieved. The present strategy offers an alternative route for ultrasensitive photodetectors with fast response.

Ultralow Light‐Power Consuming Photonic Synapses Based on Ultrasensitive Perovskite/Indium‐Gallium‐Zinc‐Oxide Heterojunction Phototransistors

AbstractThe brain‐inspired neuromorphic parallel computing has become one of the most promising technologies for efficient information processing by overcoming the von Neumann bottleneck of sequential operations. Synapses transmit information among neurons and act as the basic component in neuromorphic computing platforms. Despite the rapid advances in developing artificial synapses, most synaptic devices function electronically and thus numerous merits for photonics such as visual/imaging information processing, less corsstalk, and fast response, have to be compromised. Herein, a light‐stimulated synaptic device (photonic synapses) based on perovskite/In‐Ga‐Zn‐O heterojunction phototransistor is reported. The combination of high‐efficiency light absorber, high‐mobility channel, and heterojunction device architecture leads to efficient photon‐to‐electron conversion and intrinsic high‐gain mechanism for such light‐stimulated synapses. As a result, high performance photonic synapses are obtained with the basic functions of excitatory postsynaptic current (EPSC), paired‐pulse facilitation (PPF), and short‐term memory to long‐term memory conversion (STM‐LTM). Importantly, owing to the ultrasensitive photodetection characteristics, the light power consumption of such photonic artificial synapse can be as low as 2.6 picojoule. This study proposes a simple, efficient, and industry‐compatible device concept providing the photosensitive synapses for photonic neural networks by combining the merits of appropriate materials and device architecture.

Ambipolar Photoresponsivity in an Ultrasensitive Photodetector Based on a WSe2/InSe Heterostructure by a Photogating Effect.

Ambipolar photoresponsivity mainly originates from intrinsic or interfacial defects. However, these defects are difficult to control and will prolong the response speed of the photodetector. Here, we demonstrate tunable ambipolar photoresponsivity in a photodetector built from vertical p-WSe2/n-InSe heterostructures with photogating effect, exhibiting ultrahigh photoresponsivity from -1.76 × 104 to 5.48 × 104 A/W. Moreover, the photodetector possesses broadband photodetection (365-965 nm), an ultrahigh specific detectivity (D*) of 5.8 × 1013 Jones, an external quantum efficiency of 1.86 × 107%, and a rapid response time of 20.8 ms. The WSe2/InSe vertical architecture has promising potential in developing high-performance nano-optoelectronics.

Recent progress of silicon integrated light emitters and photodetectors for optical communication based on two-dimensional materials

Van der Waals materials are expected to meet the miniaturization and integration challenges in photonic integrated circuits (PIC) as active devices for optical communication. Recently, ultralow threshold lasers, ultra-sensitive or large bandwidth photodetectors have been demonstrated on silicon photonics platforms that are compatible with the state-of-the-art CMOS process. Here we summarize the characteristics of these hetero-integrated light-emitting and photodetecting devices, with focuses on materials, physical mechanisms, and device performances. We also discuss the strategies of future PIC architectures for valley-photonics, hybrid and 3D integrations. This review aims to summarize the most recent progress and to help identify the challenges and opportunities in this rapidly developing area.

Development of ultra-sensitive broadband photodetector: a detailed study on hidden photodetection-properties of TiS2 nanosheets

We report an ultra-sensitive broadband photodetector based on horizontally aligned titanium disulfide nanosheets (TNs). Firstly, TNs were synthesized using the chemical vapor transport (CVT) technique to develop the photodetector, and then as-prepared TNs were deposited horizontally aligned between the interdigitated electrodes (IDEs) using the dielectrophoresis (DEP) technique. The photodetection performance of the as-prepared photodetector was analysed by illuminating the device with different wavelength low-power LED lights. The sensitivity of the as-developed photodetector has been studied for varying wavelength range (375 nm, 405 nm, 455 nm, 617 nm, 855 nm, 1050 nm) as well as for different power densities of individual incident lights. The as-developed photodetector shows high photoresponse for all mentioned wavelengths and shows a rapid response (10s) and recovery (10s) with ultra-high responsivity (1.174 × 104 AW−1), quantum efficiency (3.20 × 104 AW−1nm−1) as well as detectivity (3.039 × 1011 Jones) for 455 nm wavelength and 0.086 mW/mm2 power density of incident light. The ON/OFF ratio of the as-developed photodetector is found ultra-high i.e. 28.54. Its performance with respect to external bias voltage has also been studied and reported in the manuscript. The as-prepared TNs based photodetector shows many advantageous features like high stability and repeatability. The demonstrated ultra-sensitive photoresponse of as-prepared photodetector suggests the effectiveness of TNs for improving the characteristics of modern optoelectronic devices.

Superior UV photodetector performance of TiO2 films using Nb doping

Titanium dioxide (TiO2) is one of the excellent materials used for photodetector applications due to its high photoactive nature. In this research, highly sensitive ultra-violet (UV) photodetectors with high detectivity and external quantum efficiency (EQE) are developed by depositing Nb-doped TiO2 (TNO) films onto a Si/SiO2 substrate at different Nb concentrations. The doping effect of Nb on the electronic structure and photodetector performance of TiO2 films has been investigated. The charge compensation mechanism due to Nb-doping has been explained using X-ray photoelectron spectroscopy. Lower doping concentrations of Nb5+ result in creating a Ti vacancy and an excess electron per Nb atom, contributing to the enhanced photocurrent. The metal-semiconductor-metal (M-S-M) structure of the device generates an ohmic-contact and the Si/SiO2 layer assisted toward reducing the surface recombination. All these factors cause an enhancement in the photocurrent, detectivity, and EQE of the TNO photodetector. Finally, the optimized TNO film grown using 1.0 at.% Nb shows improved photodetector properties and is suitable for ultra-sensitive UV photodetector applications.