Photoresponsivity Values Research Articles

A light-detecting Ru(II)/Si heterojunction system involving a binuclear Ru (II) complex with pyridine-2,6-diimine (pydim) ligand

A meticulously detailed chemical procedure was employed to synthesize the Ru (II)-containing pyridine-2,6-diimine (pydim) organometallic complex. The resulting complex was then applied to Al-coated Si wafers using the spin-coating technique, leading to the production of Al/Ru(II) organometallic complex/n-Si/Al photodiodes. The light responsiveness of these photodiodes was demonstrated through the acquisition of I-V and I-t characteristics. Subsequently, essential parameters such as ideality factor, photosensitivity, barrier height, and photoresponse values were evaluated based on the obtained I-V and I-t plots. The calculations yielded ideality factors and barrier heights, resulting in average values of 6.41 and 0.552 eV, respectively. Furthermore, an in-depth analysis of the electrical properties of the diodes was conducted using G-V and C-V assessments, revealing a strong dependence on AC signal frequency. This investigation underscored that the observed frequency-related electrical behaviour is rooted in series resistance and interface states.

SnS2 Thin Film with In Situ and Controllable Sb Doping via Atomic Layer Deposition for Optoelectronic Applications

AbstractSnS2 stands out as a highly promising 2D material with significant potential for applications in the field of electronics and photovoltaic technologies. Numerous attempts have been undertaken to modulate the physical properties of SnS2 by doping with various metal ions. Here, a series of Sb‐doped SnS2 is deposited via atomic layer deposition (ALD) super‐cycle process and compared its crystallinity, composition, and optical properties to those of pristine SnS2. It is found that the increase in the concentration of Sb is accompanied by a gradual reduction in the Sn and S binding energies. The work function is increased upon Sb doping from 4.32 eV (SnS2) to 4.75 eV (Sb‐doped SnS2 with 9:1 ratio). When integrated into photodetectors, the Sb‐doped SnS2 showed improved performance, demonstrating increased peak photoresponsivity values from 19.5 to 27.8 A W−1 at 405 nm, accompanied by an improvement in response speed. These results offer valuable insights into next‐generation optoelectronic applications based on SnS2.

Narrow-band n-GaN/n-Si isotype heterojunction photodiode: A simplified approach for photodiode development

An innovative approach has been explored to fabricate a high-performance photodiode in semiconductor device production, utilizing the thermal evaporation technique to grow GaN thin films. Structural analyzes were conducted on both as-deposited and annealed samples, and their properties were determined using various characterization techniques, including FESEM, XRD, XPS, Hall effect, photoluminescence, and UV-Vis spectrophotometer measurements. Valuable information has been gained about the potential of this alternative approach for fabricating GaN-based electronic devices. In this study, Al/n+-GaN/n-Si/Ag (as-deposited GaN) and Al/n-GaN/n-Si/Ag (annealed GaN) structures have been fabricated. It was found that the device produced from the as-deposited GaN thin film exhibited better performance than the annealed one. The isotype heterojunction n+-GaN/n-Si photodiode exhibited exceptional performance in detecting NIR light at a wavelength of 1050 nm under a 0 V bias. It has a full-width at half-maximum (FWHM) value of 120 nm and achieved a photoresponsivity value of 355 mA/W at a light output of 10 mW/cm². It is further supported by its external quantum efficiency of 42% and detectivity value of 6.93×1011 Jones at the peak wavelength and very fast response speed with ∼33 µs rise/fall times. These findings highlight the potential of photodiode as an efficient narrow-band in the NIR region.

Engineering surface state density of monolayer CVD grown 2D MoS2 for enhanced photodetector performance.

This study demonstrates the effect of nitrogen doping on the surface state densities (Nss) of monolayer MoS2 and its effect on the responsivity and the response time of the photodetector. Our experimental results shows that by doping monolayer MoS2 by nitrogen, the surface state (Nss) increases thereby increasing responsivity. The mathematical model included in the paper supports the relation of photocurrent gain and its dependency on trap level which states that the increasing the trap density increases the photocurrent gain and the same is observed experimentally. The experimental results at room temperature revealed that nitrogen doped MoS2 have a high NSS of 1.63 X 1013 states/m2/eV compared to undoped MoS2 of 4.2 x 1012 states/m2/eV. The increase in Nss in turn is the cause for rise in trap states which eventually increases the value of photo responsivity from 65.12 A/W (undoped MoS2) to 606.3 A/W (nitrogen doped MoS2). The response time calculated for undoped MoS2 was 0.85 sec and for doped MoS2 was 0.35 sec. Finally, to verify the dependence of surface states on the responsivity, the surface states were varied by varying temperature and it was observed that upon increment in temperature, the surface states decreases which causes the responsivity values also to decrease.

Fabrication of thin film solar cell based on CoO-CoS/P2-Amino-1-mercaptobenzene/polypyrrole with additional promising sensitivities to photons in a broad optical region

The production of a thin-film solar cell device, employing CoO-CoS/P2-Amino-1-mercaptobenzene/polypyrrole (CoO-CoS-P2AMB/Ppy), showcases enhanced sensitivity across a broad optical spectrum. This achievement is realized through a one-pot polymerization process involving 2-Amino-1-mercaptobenzene, Co(NO3)2, and K2S2O8. Notably, the polymerization reaction incorporates the inclusion of a Ppy seeding layer into the solution. To comprehensively characterize the synthesized materials, an array of analytical tools is employed. Subsequently, the CoO-CoS-P2AMB/Ppy device undergoes rigorous testing under diverse light conditions, including darkness, white light, and monochromatic light. These conditions aim to assess the device’s responsiveness to photons of varying energies, where the resulting current density (Jph) serves as an indicator of generated hot electrons and the overall efficiency of the fabricated device. At a potential of 2.0 V, the measured values for Jph and dark current (Jo) stand at 0.11 and 0.04 mA.cm−2, respectively. The solar cell characteristics are further evaluated through measured values for JSC (−0.01 μA.cm−2) and VOC (0.038 V), reflecting the device’s performance under solar testing conditions. In addition to its solar cell attributes, the device exhibits light-sensing behavior, quantified through calculated photoresponsivity (R) and detectivity (D) values. These values, obtained under various monochromatic lights, amount to 0.49 mA.W−1 and 1.1 × 108 Jones, respectively. The exceptional performance of the CoO-CoS-P2AMB/Ppy thin-film solar cell device, coupled with its light-sensing capabilities, positions the device as a promising candidate for commercial applications. Its potential extends to the fabrication of cost-effective thin-film sensing devices, presenting opportunities for widespread utilization in various industries.

The photodiode performances of NDI-appended ruthenium complexes

Abstract The synthesis and investigation of photoelectric studies of simple organic compounds as organic interlayers are of significant importance and widely studied. As such, we synthesized naphthalene diimide (NDI)-appended ruthenium complexes (Ru-NDIs) to function as the interface layer, and have fabricated novel Al/NDIs or Ru-NDIs/p-Si devices (D1-D4) to investigate their photoelectric properties. Subsequently, we compared and discussed the photoelectric properties of these devices after synthesis and fabrication. According to this, the band-gap energy (E g ) values of organic materials were found to range from 2.95 eV to 3.14 eV, making them ideal for solar cells applications. Additionally, the photoresponse (Pr) values of Al/NDIs or Ru-NDIs/p-Si devices (D1-D4) were found to be 59.25, 1593.08, 198.77, and 134.47, respectively. Moreover, the Al/Ru-NDIs/p-Si D2 structure exhibited the highest Pr values. Experimental results indicate that since the four optoelectronic devices arranged with the derivation of synthesized compounds have good photoresponse characteristics, they can be utilized as a photosensor or photodiodes in different electronic and optoelectronic technologies.

Enhancement of the Visible Light Photodetection of Inorganic Photodiodes via Additional Quantum Dots Layers.

Visible light photodetectors are extensively researched with transparent metal oxide holes/electron layers for various applications. Among the metal oxide transporting layers, nickel oxide (NiO) and zinc oxide (ZnO) are commonly adopted due to their wide band gap and high transparency. The objective of this study was to improve the visible light detection of NiO/ZnO photodiodes by introducing an additional quantum dot (QD) layer between the NiO and ZnO layers. Utilizing the unique property of QDs, we could select different sizes of QDs and responsive light wavelength ranges. The resulting red QDs utilized device that could detect light starting at 635 nm to UV (Ultra-violet) light wavelength and exhibited a photoresponsivity and external quantum efficiency (EQE) of 14.99 mA/W and 2.92% under 635 nm wavelength light illumination, respectively. Additionally, the green QDs, which utilized a device that could detect light starting at 520 nm, demonstrated photoresponsivity values of 8.34 mA/W and an EQE of 1.99% under 520 nm wavelength light illumination, respectively. In addition, we used X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) to investigate the origin of the photocurrents and the enhancement of the device's performance. This study suggests that incorporating QDs with metal oxide semiconductors is an effective approach for detecting visible light wavelengths in transparent optoelectronic devices.

Low-Power Phototransistor with Enhanced Visible-Light Photoresponse and Electrical Performances Using an IGZO/IZO Heterostructure.

In this study, we demonstrated the effective separation of charge carriers within the IGZO/IZO heterostructure by incorporating IZO. We have chosen IGZO for its high mobility and excellent on-off switching behavior in the front channel of our oxide-oxide heterostructure. Similarly, for an additional oxide layer, we have selected IZO due to its outstanding electrical properties. The optimized optoelectronic characteristics of the IGZO/IZO phototransistors were identified by adjusting the ratio of In:Zn in the IZO layer. As a result, the most remarkable traits were observed at the ratio of In:Zn = 8:2. Compared to the IGZO single-layer phototransistor, the IGZO/IZO(8:2) phototransistor showed improved photoresponse characteristics, with photosensitivity and photoresponsivity values of 1.00 × 107 and 89.1 AW-1, respectively, under visible light wavelength illumination. Moreover, the electrical characteristics of the IGZO/IZO(8:2) transistor, such as field effect mobility (μsat) and current on/off ratio (Ion/Ioff), were highly enhanced compared to the IGZO transistor. The μsat and Ion/Ioff were increased by about 2.1 times and 2.3 times, respectively, compared to the IGZO transistor. This work provides an approach for fabricating visible-light phototransistors with elevated optoelectronic properties and low power consumption based on an oxide-oxide heterostructure. The phototransistor with improved performance can be applied to applications such as color-selective visible-light image sensors and biometric sensors interacting with human-machine interfaces.

Decoration of Poly-3-methyl Aniline with As(III) Oxide and Hydroxide as an Effective Photoelectrode for Electroanalytical Photon Sensing with Photodiode-like Behavior.

This study achieved the decoration of poly-3-methyl aniline (P3MA) with As2O3-As(OH)3 using K2S2O8 and NaAsO2 on the 3-methyl aniline monomer. This resulted in a highly porous nanocomposite polymer composite with wide absorption optical behavior, an average crystalline size of 22 nm, and a 1.73 eV bandgap. The photoelectrode exhibited a great electrical response for electroanalytical applications, such as photon sensing and photodiodes, with a Jph of 0.015 mA/cm2 and Jo of 0.004 mA/cm2. The variable Jph values ranged from 0.015 to 0.010 mA/cm2 under various monochromatic filters from 340 to 730 nm, which demonstrates high sensitivity to wavelengths. Effective photon numbers were calculated to be 8.0 × 1021 and 5.6 × 1021 photons/s for these wavelength values, and the photoresponsivity (R) values were 0.16 and 0.10 mA/W, respectively. These high sensitivities make the nanocomposite material a promising candidate for use in photodetectors and photodiodes, with potential for commercial applications in highly technological systems and devices. Additionally, the material opens up possibilities for the development of photodiodes using n- and p-type materials.

Preparation and Characterization of Polyhedron Mn(III) Oxide/-β-Mn(IV) Oxide/Poly-o-chloroaniline Porous Nanocomposite for Electroanalytical Photon Detection

Poly-o-chloroaniline (POCA) and Mn2O3/β-MnO2/POCA porous nanocomposite are both synthesized using oxidative polymerization, with K2S2O8 and KMnO4 as oxidants, respectively. The materials are characterized to confirm their optical, morphological, crystalline, chemical, and elemental properties. The nanocomposite exhibits superior optical properties compared to POCA. The promising optical characteristics make the nanocomposite an attractive candidate for light-sensing applications. Through electrical estimation, the nanocomposite photodetector displays the highest sensitivity between 340 and 440 nm, with Jph (current density) of 0.14 and 0.13 mA cm−2, correspondingly, and an estimated photon number of 7.461021 and 6.93 × 1021 photons/s, respectively. At 340 and 440 nm, the calculated photoresponsivity (R) values are 0.73 and 0.64 mA W−1, respectively, while the estimated detectivity (D) values are 1.64 × 108 and 1.45 × 108 Jones, respectively. These promising results indicate that the fabricated photodetector can soon potentially estimate light wavelengths and photon numbers in various industrial applications.

Photodetector-Based Material from a Highly Sensitive Free-Standing Graphene Oxide/Polypyrrole Nanocomposite

This paper describes the establishment of free-standing rolled graphene oxide (roll-GO) and polypyrrole (Ppy) using a modified Hummer method and oxidative polymerization. Then, a photodetector was created by removing a thin film of the free-standing rolled graphene oxide from a filter paper and attaching it to a tape. The chemical structure of the roll-GO was confirmed using XRD and FTIR analysis, while SEM and TEM showed that it was rolled in nature. The material had a small bandgap of 2.4 eV and a high current density in light conditions. The photodetector responded well to monochromatic light, with Jph values changing from 0.027 to 0.019 mA/cm2 as the light wavelengths decreased from 340 to 730 nm. The photoresponsivity (R) and detectivity (D) values were high, at 340 nm (0.27 mA/W and 6.0 × 107 Jones, respectively) and at 730 nm (0.19 and 4.25 × 107 Jones, respectively). The addition of Ppy improved these parameters, with the Ppy/roll-GO/tape photoelectrode showing excellent R and D values of 0.33 mA/W and 7.34 × 107 Jones, respectively. Furthermore, the production of a photocurrent at V = 0 indicated that the Ppy/roll-GO layer could be used for solar cell applications. Overall, the results suggest that the prepared free-standing Ppy/roll-GO/tape photodetector has high potential for use in the optical region between 340 and 730 nm and may be suitable for industrial applications.

Enhanced visible and IR light-sensing performance of photoconductive VO2 (M1) nanorods thin film

In this article, we report on the enhanced photo-response of VO2 (M1) nanorods (NRs) thin film upon exposure to visible and near Infrared (NIR) light. The growth of photoconductive VO2 (M1) NRs thin film has been carried out using a pulsed laser deposition (PLD) technique. Field emission scanning electron microscopy (FESEM) showed the formation of NRs-like structures on the deposited thin film. The semiconductor-to-metal transition (SMT) properties at ∼64.8 °C and ∼59.8 °C during the heating and cooling cycle respectively confirm the deposition of VO2 (M1) thin film. The formation of VO2 (M1) thin film is also validated by Raman spectroscopy and X-ray diffraction (XRD) techniques. The photoconductivity of the pulsed laser deposited VO2 (M1) NRs thin film has been studied using the simple planar geometry upon exposure to the visible light (650 nm) and NIR light (980 nm) at 2 V and 5 V bias voltages. The estimated rise time and fall time of the photoconductive VO2 (M1) NRs thin films were about 1.88 ms and 1.9 ms upon exposure to the visible light and 1.89 and 2.4 ms upon exposure to the NIR light respectively. The photo-responsivity values of ∼1120 mA/W and ∼138 mA/W have been achieved for the visible and NIR light respectively at 5 V bias voltage. The photoconductive VO2 (M1) NRs thin film reveals highly responsive and fast visible and NIR light-sensing performance with simple planar geometry (Ag/ VO2 (M1) NRs thin film/Ag).

Modulation of Schottky Barrier Height by Nitrogen Doping and Its Influence on Responsivity of Monolayer MoS2 Photodetector

AbstractMonolayer MoS2 flakes are prepared by low‐pressure chemical vapor deposition on p‐type and n‐type silicon substrates and post‐treated under nitrogen (N2)‐rich conditions to incorporate nitrogen atoms in sulfur vacancies. Ultraviolet photoelectron spectroscopy (UPS) shows an increase in work function value by 0.47 eV and 0.53 eV compared to undoped MoS2 when grown on p and n‐type substrates, respectively. Photodetection experiments conducted for doped and undoped MoS2 grown on p‐type substrate reveal a decrease in the value of photo responsivity for N2 doped MoS2 (191 A W−1) compared with undoped MoS2 (572 A W−1). Also, MoS2 crystals grown and doped on an n‐type substrate display an important enhancement of the photoresponsivity from 63 A W−1 for undoped to 606 A W−1 for N2 doped MoS2. The modulation of Schottky barrier height for N2 doped MoS2 on p type substrate decreased whereas for n type substrate the high electric field created due to the difference in the Fermi level allows for greater separation of photogenerated charge carriers. This modulation in the photoresponsivity due to the selection of the type of substrate opens up new avenues of research and engineering of atomically thin optoelectronic devices.

Surface Morphology, Structural, Photovoltaic and Optoelectronic Properties of Diamond Like Carbon-Copper Nanostructures

In this work, we produced Cu doped diomond like carbon films using the magnetron sputtering technique and assessed their structural electrical and optoelectronic characteristics. In the atomic force microscopy (AFM) measurements, it was observed that the surface of the Cu-DLC nanocomposite films was in a granular form and the presence of cluster-like formations. D and G bands, which are the characteristic peaks of the DLC structure, were observed in the Raman spectrum, while Cu and C peaks were observed in the energy dispersive (EDX) spectrum. Photocurrent, photocapacitance, photosensitivity and photoresponse values increased depending on the increasing light intensity. However, the Cu-DLC/n-Si structure displayed low photovoltaic properties. The capacitance and conductance values were considerably affected by the increase in AC signal frequency. The series resistance and the density of the interface states exhibited low frequency dependent behavior which were obtained using the electrical characteristics of the nanocomposite films.

Chiral metal-organic framework based spin-polarized flexible photodetector with ultrahigh sensitivity

Spin-optoelectronics plays a key role in developing next-generation technologies with potential applications covering from pharmaceutical synthesis and quantum computing to optical communication. One of the most feasible ways to achieve high-performance spin optoelectronic devices is based on chiral materials. Chiral metal-organic frameworks (CMOFs), an emerging class of chiral hybrid materials, have sparked interest due to their structural variety and flexibility, order nanopores, cost-effectiveness, and unique chirality features. Herein, we have developed CMOF [Sr (9,10-adc) (DMAc)2]n based on achiral building blocks [(9,10-adc)] to detect circularly polarized light (CPL) with ultrahigh sensitivity. Their application in spin-polarized flexible detectors gives a detectivity (D∗) as high as 1.83 × 1012 jones, superior to all reported heterochiral MOF-based detectors. Meanwhile, the anisotropy factor (gIph) is up to 0.38 for CPL detection. The maximum photoresponsivity (Rph) and photogain (η) values of CMOFs reach up to 6.0 × 105 (A/W) and 1.8 × 106, respectively, which are also the record values among reported chiral MOFs. Additionally, the photodetector is mechanically flexible and durable, manifesting an important feature for wearable devices. Therefore, our study shown here is significant and timely to open a route for advancing spin-optoelectronics based on CMOF.

High responsivity n-ZnO nanorods/p-GaN heterojunction-based UV-A photodetectors

Here, we report the fabrication of ZnO/p-GaN based high responsivity ultraviolet (UV) photodetector. Hydrothermal technique has been followed to grow ZnO nanorods; where two different types of precursors (nitrate and chloride) were used for the growth of nanorods. Interestingly, it was found that the ZnO nanorods grown using nitrate precursor are less prone to defect emission in comparison to the ZnO nanorods prepared using chloride-based precursor which resulted in low dark current levels. The photo-responsivity and photo-detectivity values of the as-fabricated device were calculated to be 350 mA W−1 and 3.5 × 1011 Jones, respectively at 360 nm excitation wavelength and ∼1.79 µW cm−2 excitation intensity. The demonstration of high responsivity UV detectors (at low excitation intensity values) using ZnO nanorods/GaN can pave the way toward the development of high-performance next generation UV photodetectors.

Self-powered, ultra-fast and high photoresponsivity of MoTe2/HfSe2 heterostructure broadband photovoltaic device

Due to their multifunctionality and tunable properties in electronic devices, the transition-metal dichalcogenides (TMDs) based van der Waals (vdW) heterostructures have attracted much attention and are considered a potential candidate for advanced nanoelectronics. In this work, a self-powered molybdenum ditelluride (MoTe2)/hafnium diselenide (HfSe2) vdW heterostructure-based photodetector with ohmic contacts is designed. The high rectification ratio is attained as 1.9×106, rising from the clean interface and small barrier height. Photovoltaic experiments are also carried out using laser light with a wavelength of 532–1064 nm in visible and near-infrared (VNIR) regions with different power intensities ranging from 10 to 120 nW. The photoresponsivity of MoTe2/HfSe2 is enhanced remarkably up to 1.3×103A/W with detectivity 2.6 × 1013 Jones and external quantum efficiency of 68% because of band-to-band and interlayer TMDs charge transition at a longer wavelength (1064 nm). Under incoming light with an intensity of 120 nW, rapid growth (6.8 μs) and decay times (8.7 μs) are projected because of interlayer TMDs charge transition at the longer wavelength. The obtained results showed significantly higher values than the reported vdW heterostructures. The fast response time, low recombination rate and astonishing value of photoresponsivity are the key parameters to developing highly efficient TMDs-based solar devices.

Development of a Highly Efficient Optoelectronic Device Based on CuFeO2/CuO/Cu Composite Nanomaterials.

Herein, an optoelectronic device synthesized from a CuFeO2/CuO/Cu nanocomposite was obtained through the direct combustion of Cu foil coated with Fe2O3 nanomaterials. The chemical, morphological, and optical properties of the nanocomposite were examined via different techniques, such as XRD, XPS, TEM, SEM, and UV/Vis spectrophotometer. The optical reflectance demonstrated a great enhancement in the CuFeO2 optical properties compared to CuO nanomaterials. Such enhancements were clearly distinguished through the bandgap values, which varied between 1.35 and 1.38 eV, respectively. The XRD and XPS analyses confirmed the chemical structure of the prepared materials. The produced current density (Jph) was studied in dark and light conditions, thereby confirming the obtained optoelectronic properties. The Jph dependency to monochromatic wavelength was also investigated. The Jph value was equal to 0.033 mA·cm−2 at 390 nm, which decreased to 0.031 mA·cm−2 at 508 nm, and then increased to 0.0315 mA·cm−2 at 636 nm. The light intensity effects were similarly inspected. The Jph values rose when the light intensities were augmented from 25 to 100 mW·cm−2 to reach 0.031 and 0.05 mA·cm−2, respectively. The photoresponsivity (R) and detectivity (D) values were found at 0.33 mA·W−1 and 7.36 × 1010 Jones at 390 nm. The produced values confirm the high light sensitivity of the prepared optoelectronic device in a broad optical region covering UV, Vis, and near IR, with high efficiency. Further works are currently being designed to develop a prototype of such an optoelectronic device so that it can be applied in industry.

Facile Preparation of Flexible Lateral 2D MoS2 Nanosheets for Photoelectrochemical Hydrogen Generation and Optoelectronic Applications

Two-dimensional (2D) materials have attracted significant attention with their high optical response due to their interesting and unique fundamental phenomena. A lateral 2D MoS2 nanosheets was prepared via a facile one-step electrophoretic deposition method on polyethylene terephthalate (PET)/ITO. These nanosheets have been used as photoelectrode materials for photoelectrochemical (PEC) hydrogen generation and optoelectronics. The chemical structure and morphology were confirmed using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Raman, scanning electron microscope (SEM), and transmission electron microscopy (TEM). The optical absorbance of the 2D MoS2 nanosheets extended to the UV, Vis, and near-IR regions with a bandgap value of 1.59 eV. The testing of the prepared photoelectrode material, PET/ITO/MoS2, was carried out through a three-electrode system, in which the current density (Jph) value represents the rate of H2 gas evaluated. The Jph enhanced under light illumination compared to the dark conditions with values of 0.4 to 0.98 mA·cm−2, respectively. The produced photocurrent at V = 0 V was 0.44 mA·cm−2. This confirms the great abilities of the PET/ITO/MoS2 photoelectrode in light detection and hydrogen generation with high photoresponsivity values. Soon, our team will work on the development of a prototype of this three-electrode cell to convert the water directly into H2 fuel gas that could be applied in houses and factories, or even in advanced technology such as spacecraft and airplane F-35s by providing H2 gas as a renewable energy source.

Photoemission of Plasmonic Gold Nanostars in Laser-Controlled Electron Current Devices for Technical and Biomedical Applications.

The main goal of this work was to modify the previously developed blade-type planar structure using plasmonic gold nanostars in order to stimulate photofield emission and provide efficient laser control of the electron current. Localization and enhancement of the field at the tips of gold nanostars provided a significant increase in the tunneling electron current in the experimental sample (both electrical field and photofield emission). Irradiation at a wavelength in the vicinity of the plasmon resonance (red laser) provided a gain in the photoresponse value of up to 5 times compared to irradiation far from the resonance (green laser). The prospects for transition to regimes of structure irradiation by femtosecond laser pulses at the wavelength of surface plasmon resonance, which lead to an increase in the local optical field, are discussed. The kinetics of the energy density of photoinduced hot and thermalized electrons is estimated. The proposed laser-controlled matrix current source is promising for use in X-ray computed tomography systems.