Metal-semiconductor-metal Devices Research Articles

Orientation-Dependent Photoconductivity of Quasi-2D Nanocrystal Self-Assemblies: Face-Down, Edge-Up Versus Randomly Oriented Quantum Wells.

Here, strongly orientation-dependent lateral photoconductivity of a CdSe monolayer colloidal quantum wells (CQWs) possessing short-chain ligands is reported. A controlled liquid-air self-assembly technique is utilized to deliberately engineer the alignments of CQWs into either face-down (FO) or edge-up (EO) orientation on the substrate as opposed to randomly oriented (RO) CQWs prepared by spin-coating. Adapting planar configuration metal-semiconductor-metal (MSM) photodetectors, it is found that lateral conductivity spans ≈2 orders of magnitude depending on the orientation of CQWs in the film in the case of utilizing short ligands. The long native ligands of oleic acid (OA) are exchanged with short-chain ligands of 2-ethylhexane-1-thiol (EHT) to reduce the inter-platelet distance, which significantly improved the photoresponsivity from 4.16, 0.58, and 4.79 mA W-1 to 528.7, 6.17, and 94.2mAW-1, for the MSM devices prepared with RO, FO, and EO, before and after ligands exchange, respectively. Such CQW orientation control profoundly impacts the photodetector performance also in terms of the detection speed (0.061 s/0.074 s for the FO, 0.048 s/0.060 s for the EO compared to 0.10 s/0.16 s for the RO, for the rise and decay time constants, respectively) and the detectivity (1.7×1010, 2.3×1011, and 7.5×1011 Jones for the FO, EO, and RO devices, respectively) which can be further tailored for the desired optoelectronic device applications. Attributed to charge transportation in colloidal films being proportional to the number of hopping steps, these findings indicate that the solution-processed orientation of CQWs provides the ability to tune the photoconductivity of CQWs with short ligands as another degree of freedom to exploit and engineer their absorptive devices.

Novel supramolecular luminescent metallogels containing Tb(iii) and Eu(iii) ions with benzene-1,3,5-tricarboxylic acid gelator: advancing semiconductor applications in microelectronic devices.

A novel strategy was employed to create supramolecular metallogels incorporating Tb(iii) and Eu(iii) ions using benzene-1,3,5-tricarboxylic acid (TA) as a gelator in N,N-dimethylformamide (DMF). Rheological analysis demonstrated their mechanical robustness under varying stress levels and angular frequencies. FESEM imaging revealed a flake-like hierarchical network for Tb-TA and a rod-shaped architecture for Eu-TA. EDX analysis confirmed essential chemical constituents within the metallogels. FT-IR, PXRD, Raman spectroscopy, and thermogravimetric analysis assessed their gelation process and material properties, showing semiconducting characteristics, validated by optical band-gap measurements. Metal-semiconductor junction-based devices integrating Al metal with Tb(iii)- and Eu(iii)-metallogels exhibited non-linear charge transport akin to a Schottky diode, indicating potential for advanced electronic device development. Direct utilization of benzene-1,3,5-tricarboxylic acid and Tb(iii)/Eu(iii) sources underscores their suitability as semiconducting materials for device fabrication. This study explores the versatile applications of Tb-TA and Eu-TA metallogels, offering insights for material science researchers.

A 250 nm high-performance AlGaN-based metal–semiconductor–metal deep ultraviolet detector

The present work reports a Al0.67Ga0.33N Metal–Semiconductor–Metal (MSM) detector with a high quantum efficiency (QE) by metal organic chemical vapor deposition (MOCVD) and Standard photolithography. As previously reported, the electrode spacing between the metal fingers of MSM detectors, annealing temperature, and electrode material affect the performance of detectors. Our work demonstrates a high QE detector by optimizing the electrode and annealing temperature. At 14 V bias, the ultraviolet-to-visible rejection ratio is measured as high as 1000. It is also found that the responsivity increases with the bias voltage. Due to the influence of the image force and tunnel effect, the QE exceeds 100 % and the responsivity reaches 4.24 A/W near 250 nm. The specific detectivity (D*) also reaches 1.32 × 1011 Jones. Compared with the literature, this is the highest QE of MSM devices with Ti electrodes on the AlGaN layer at this wavelength. This gain mechanism should be related to trapping photo carriers at the semiconductor/metal interface, image-force lowering of Schottky barrier height, and the expansion of the space charge layer (SCR).

Photoluminescence properties and DFT simulations of the Cr ion-implanted (100)-oriented β-Ga2O3 single crystals

Beta-gallium oxide (β-Ga2O3) with tunable optical and electrical properties has great potential in power metal-semiconductor devices. In this work, (100)-oriented β-Ga2O3 single crystals were implanted with 190 keV Cr ions at different fluencies, and their photoluminescence, band structures, and electronic properties have been studied in detail. Our results clearly show that ion implantation-induced lattice damage could be recovered and the implanted Cr ions in (100)-oriented β-Ga2O3 can be activated to produce NIR (R-lines and broadband) emissions after the post-implantation annealing at 900 °C. Temperature-dependent photoluminescence (TDPL) measurements indicate that the increasing temperature could lead to weakness and redshifts of the R-lines emissions centered at about 692 nm, while the broadband emission centered at about 713 nm enhanced because of a higher thermal occupation at the 4T2 state than at the 2E state. Results from Density functional theory (DFT) calculations demonstrate that the Ga atom’s replacements with Cr atoms could occur at the tetrahedral or octahedral sites of the lattices, which allows the Cr atoms to be activated to act as the NIR emission centers.

Plasmonic Near-Infrared Photoconductor Based on Hot Hole Collection in the Metal-Semiconductor-Metal Junction.

Harvesting energetic carriers from plasmonic resonance has been a hot topic in the field of photodetection in the last decade. By interfacing a plasmonic metal with a semiconductor, the photoelectric conversion mechanism, based on hot carrier emission, is capable of overcoming the band gap limitation imposed by the band-to-band transition of the semiconductor. To date, most of the existing studies focus on plasmonic structural engineering in a single metal-semiconductor (MS) junction system and their responsivities are still quite low in comparison to conventional semiconductor, material-based photodetection platforms. Herein, we propose a new architecture of metal-semiconductor-metal (MSM) junctions on a silicon platform to achieve efficient hot hole collection at infrared wavelengths with a photoconductance gain mechanism. The coplanar interdigitated MSM electrode’s configuration forms a back-to-back Schottky diode and acts simultaneously as the plasmonic absorber/emitter, relying on the hot-spots enriched on the random Au/Si nanoholes structure. The hot hole-mediated photoelectric response was extended far beyond the cut-off wavelength of the silicon. The proposed MSM device with an interdigitated electrode design yields a very high photoconductive gain, leading to a photocurrent responsivity up to several A/W, which is found to be at least 1000 times higher than that of the existing hot carrier based photodetection strategies.

Schottky type photodiodes with organic Co‐complex and Cd‐complex interlayers

Cd and Co metal centered nicotinamide/nicotinic acid complexes were synthesized by chemical reactions. The complexes were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT‐IR), powder X‐ray diffractometer (P‐XRD), ultraviolet–visible (UV–Vis) spectrometer, and scanning electron microscopy (SEM) with energy dispersive X‐ray (EDX) detector. The complexes were used as interfacial layers in between Al and p‐Si to fabricate Al/Cd‐complex/p‐Si and Al/Co‐complex/p‐Si metal semiconductor devices. The devices were characterized by current–voltage (I‐V) and current‐time (I‐t) measurements under dark and various light power intensities. The ideality factor, barrier height, and series resistance values were extracted from I‐V measurements and discussed in detail by various techniques. The I‐t measurements were used to derive various detector parameters such as responsivity, photosensitivity, and specific detectivity for various power values and wavelength regions. The devices exhibited good photodiode and photodetector performance according to results, and they can be improved for optoelectronic applications.

Fabrication of UV ZnO NRS photodetector based on seeded silicon substrate via the drop-casting technique

PurposeThe purpose of this study is to fabricate an ultraviolet (UV) metal-semiconductor-metal (MSM) photodetector based on zinc oxide nanorods (ZnO NRs) grown on seeded silicon (Si) substrate that was prepared by a low-cost method (drop-casting technique).Design/methodology/approachThe drop-casting method was used for the seed layer deposition, the hydrothermal method was used for the growth of ZnO NRs and subsequent fabrication of UV MSM photodetector was done using the direct current sputtering technique. The performance of the fabricated MSM devices was investigated by current–voltage (I–V) measurements. The photodetection mechanism of the fabricated device was discussed.FindingsSemi-vertically high-density ZnO (NRs) were effectively produced with a preferential orientation along the (002) direction, and increased crystallinity is confirmed by X-ray diffraction analysis. Photoluminescence results show a high UV region. The fabricated MSM UV photodetector showed that the ZnO (NRs) MSM device has great stability over time, high photocurrent, good sensitivity and high responsivity under 365 nm wavelength illumination and 0 V, 1 V, 2 V and 3 V applied bias. The responsivity and sensitivity for the fabricated ZnO NRs UV photodetector are 0.015 A W-1, 0.383 A W-1, 1.290 A W-1 and 1.982 A W-1 and 15,030, 42.639, 100.173 and 334.029, respectively, under UV light (365 nm) illumination at (0 V, 1 V, 2 V and 3 V).Originality/valueThis paper uses the drop-casting technique and the hydrothermal method as simple and low-cost methods to fabricate and improve the ZnO NRs photodetector.

Effect of Irradiation (SRFE) on MSM Photodetectors Device

This paper presents the effect of high energy irradiation expose on metal-semiconductor-metal (MSM) photodetectors device. High energy radiation may impact to lattice structure of semiconductor device. The most impact of radiation on MSM device had been studied base on polycrystalline silicon. Based on our research in SRFE process exposed on P-N power device, radiation will interact with device mechanism and structure that change electrical properties of device. However, MSM device show electrical properties change after irradiation exposure process by photocurrent increased around 4 times when compare with non-irradiated.

Photoconductive and photovoltaic metal-semiconductor-metal κ-Ga2O3 solar-blind detectors with high rejection ratios

The metal-semiconductor-metal (MSM) structure is a popular architecture for developing Ga2O3 solar blind photodetectors. The nature of metal-semiconductor contact is decisive for the operation mode, gain mechanism and device performances. In this contribution, κ-Ga2O3 MSM solar-blind photodetectors with Ti/Ga2O3 Ohmic and Ni/Ga2O3 Schottky contacts were constructed on the high-quality Si-doped κ-Ga2O3 epilayer grown by hydride vapor phase epitaxy. The Ti/κ-Ga2O3/Ti Ohmic MSM device is operated in a photoconductive mode, exhibiting a maximum responsivity of 322.5 A W−1 and a high rejection ratio of over 105, but with an undesirable sub-gap response and high dark current. In comparison, the Ni/Ga2O3/Ni photodiode with a back-to-back Schottky configuration is operated in a mixed photovoltaic and photoconductive mode, demonstrating a decent photoresponsivity of 0.37 A W−1, a maintained high rejection ratio of 1.16 × 105, a detectivity of 3.51 × 1013 Jones and the elimination of slow photoresponse from sub-gap states. The frequency-dependent photoresponse and transient photocurrent characteristics indicate that the persistent photoconductivity effect is responsible for the high gain achieved in the Ti/Ga2O3/Ti photoconductor, and the dominant slow transient decay component is a fingerprint of photoexcited carrier trapping and repopulation. The response speed is improved in the Ni/Ga2O3/Ni Schottky MSM device, whereas carrier transport across interdigitated fingers is affected by bulk traps, limiting the overall response-bandwidth merit.

Highly efficient UV detection in a metal–semiconductor–metal detector with epigraphene

We show that epitaxial graphene on silicon carbide (epigraphene) grown at high temperatures (T >1850 °C) readily acts as material for implementing solar-blind ultraviolet (UV) detectors with outstanding performance. We present centimeter-sized epigraphene metal–semiconductor–metal (MSM) detectors with a peak external quantum efficiency of η ∼ 85% for wavelengths λ = 250–280 nm, corresponding to nearly 100% internal quantum efficiency when accounting for reflection losses. Zero bias operation is possible in asymmetric devices, with the responsivity to UV remaining as high as R = 134 mA/W, making this a self-powered detector. The low dark currents Io ∼ 50 fA translate into an estimated record high specific detectivity D = 3.5 × 1015 Jones. The performance that we demonstrate, together with material reproducibility, renders epigraphene technologically attractive to implement high-performance planar MSM devices with a low processing effort, including multi-pixel UV sensor arrays, suitable for a number of practical applications.

(INVITED) Opto-electronic properties of solution-synthesized MoS2 metal-semiconductor-metal photodetector

We report a simple fabrication method for metal-semiconductor-metal (MSM) photodetectors using solution-synthesized MoS2 films as the semiconductor channel and pure indium for the metal contacts. Resonance Raman spectroscopy has been used to confirm the growth of ultra-thin MoS2 films. Due to the low work function of indium, the back-to-back indium-MoS2 Schottky junctions formed relatively low Schottky barrier height (0.43 eV), which has been calculated using the thermionic field emission model. Moreover, the MSM device shows good responsivity (22 mA/W) under white light illumination. The MoS2-MSM device possesses higher photoelectrical response in the visible and near IR region compared to UV due to the indirect bandgap of ultra-thin MoS2 film which has been estimated to be 1.38 eV. These findings reveal the significance of using low work function metals like indium as contacts for layered transition metal dichalcogenides (TMDC) films (produced by low cost solution-based techniques), particularly MoS2, in order to design semiconductor devices with efficient opto-electronic performance.

Self-powered UV photodetector performance optimization based on Ag nanoparticles-encapsulated-ZnO nanorods by photo-deposition method

Simple and cost-effective hydrothermal technique combined with the photo-deposition method was successfully employed to synthesize silver nanoparticles-encapsulated-zinc oxide nanorods (Ag NPs/ZnO NRs) arrays on Silicon (Si) substrate for the fabrication of self-power metal-semiconductor-metal (MSM) Ultraviolet (UV) photodetector device. The Field Emission Scanning Electron Microscope (FESEM) results showed that there was a noticeable change in the morphological surface of ZnO NRs after the photo-deposition process, corroborating the presence of Ag NPs. For Ag NPs/ZnO NRs photodetector, the current-voltage (I-V) characteristics demonstrated that its conductivity was significantly enhanced compared to the photodetector without Ag NPs. For the MSM device fabricated with (Ag NPs/ZnO NRs), it has recorded a responsivity value of 42.79 A W−1, and external quantum efficiency (EQE) of 13,436.06% at 15 V bias voltage. Lastly, the modified device has a sensitivity of 18503% at 0 V bias voltage, making the device suitable as self-powered photodetectors.

Comparison of n and p type Si-based Schottky photodiode with interlayered Congo red dye

We synthesized a thin film of Au nanoparticles-decorated Congo red (CR) dye on both n-Si and p-Si substrates by the spin coating technique. UV–Vis spectrometer was used to determine the absorbance and band gap of the CR film. Transmission electron microscope (TEM) was used to assess the distribution of Au nanoparticles on the CR dye film. Then, the metal-semiconductor devices were fabricated by evaporation of Co metal and Al ohmic contacts on the front and back surfaces of the CR film-covered substrates, respectively. Thus, Co/CR:Au/n-Si and Co/CR:Au/p-Si Schottky photodiodes were fabricated and characterized by I–V measurements under dark and various light power illumination intensities at room temperature. The devices exhibited good rectifying behaviors and low barrier heights. Various diode parameters such as ideality factor, barrier height, and series resistance values were calculated and compared for the two fabricated photodiodes. The Co/CR:Au/n-Si and Co/CR:Au/p-Si devices exhibited good photodiode and photodetector properties. Various detection parameters revealed that the obtained devices can be improved for optoelectronic applications.

CuO nanowire-based metal semiconductor metal infrared photodetector

Metal–semiconductor-metal (MSM) infrared photodetector-based Ag/CuO NW/Ag was fabricated using glancing angle deposition technique integrated RF sputtering machine. The transmission electron microscope confirmed the average length and diameter of the fabricated CuO NW were ~ 450 nm ± 7 nm and 135 nm ± 5 nm, respectively. Moreover, selective area electron diffraction pattern showed that the growth NW was polycrystalline in nature with d-spacing of 0.21 nm and 0.33 nm. The indirect band gap of CuO NW sample was found to be 1.4 eV. Moreover, Ag/CuO/Ag MSM device exhibited photoresponsivity of 2.9 A/W at −4 V applied bias upon exposure of 855 nm monochromatic light source (low density of power 27.29 nW). In addition, the switching responses were also measured, and the rise and fall time were found to be 0.326 s and 0.245 s, respectively.

The role of molybdenum trioxide in the change of electrical properties of Cr/MoO3/n-Si heterojunction and electrical characterization of this device depending on temperature

In this study, the molybdenum trioxide as a chemical compound with the formula MoO3 was coated between chromium (Cr) metal and n-type semiconductor (n-Si) by thermal evaporation. Using this method, Cr/MoO3/n-Si/Al heterojunction was obtained. With the thermionic emission (TE) theory, the ideality factor (n) for the reference Cr/n-Si/Al metal-semiconductor (MS) device was calculated as 1.88 and the barrier height (Φb) was calculated as 0.59 eV. On the other hand, the ideality factor for six (D1-D6) Cr/MoO3/n-Si/Al heterojunction devices obtained with MoO3 nanopowder was calculated between 1.61 and 1.69, and the barrier height was calculated as 0.69 eV, respectively. According to these results, MoO3 layer made the device's current transmission mechanism behave ideally and increased the barrier height. Current-voltage (I–V) measurements depending on temperature were performed for D1 named Cr/MoO3/n-Si/Al device, which provided the best results. Electrical parameters, such as n, Φb and series resistance (Rs), by the TE method, Cheung and Norde functions were calculated using I–V characteristic taken from the 100 K–400 K temperature range. According to the results obtained, the values of n and Rs decreased and the barrier height increased in the heterojunction device due to the increase in the temperature value. When the results were evaluated, it was observed that the current transmission of the Cr/MoO3/n-Si/Al device was compatible with the applied temperature and a significant and regular change in the temperature-dependent I–V characteristics. This finding suggests that Cr/MoO3/n-Si/Al heterojunction obtained with MoO3 is a good option for thermal sensitivity applications.

Green synthesis of graphene quantum dots and the dual application of graphene quantum dots-decorated flexible MSM p-type ZnO device as UV photodetector and piezotronic generator

A novel method to synthesize graphene sheets and graphene quantum dots (GQDs) from agricultural waste is reported in this paper. The as-prepared GQDs were decorated on the antimony (Sb)-doped zinc oxide (ZnO) nanostructures to improve the opto-electrical properties of the photodetector. Morphological studies, elemental analysis, absorption and Raman spectroscopy studies were performed on the as-prepared graphene sheets and GQDs. A GQDs-decorated, p-type Sb-doped ZnO metal–semiconductor–metal (MSM) interdigitated UV photodetector was fabricated on a flexible ITO/PET substrate. Structural, morphological and elemental analyses were performed on the GQDs-decorated nanostructures. The Hall measurements show that the device exhibits p-type conductivity with hole concentration of 3 × 1019 cm−3 and Hall mobility of 2067 cm2 V−1 s−1. It is observed from the I–V studies that the Sb-doped ZnO MSM device with GQDs exhibits 103 times higher dark and photocurrents as compared to the device without GQDs decoration. The dynamic response is measured, and the turn-on (τon) and turn-off (τoff) times are found to be 3.67 and 12.26 s, respectively. The device also exhibited piezotronic dark potential on compression at a convex arc angle. Repeated compressions and relaxations were performed on the device and it behaved as a piezotronic generator.

Investigation of cadmium-incorporated ZnO thin films for photodetector applications

Abstract Thin films of cadmium-incorporated ZnO (CZO) have been synthesized and investigated for potential light detecting applications. Epitaxial, c-axis oriented growth of CZO films was achieved using pulsed laser deposition technique. X-ray diffraction and atomic force microscopy analyses of the as-deposited CZO film were compared with those of undoped ZnO film in order to comprehend the effect of cadmium incorporation on the microstructural and electrical properties of ZnO. Hall measurements performed at 298 K revealed a high mobility of 169.26 cm2/V for the CZO film deposited on c-plane sapphire substrate. Non-alloyed contacts of indium (In) and aluminum (Al) were metalized on the film surface using thermal evaporation and current-voltage (I–V) measurements were made in the metal/semiconductor/metal (MSM) configuration at 298 K. While the In/ZnO/In device showed a linear I–V response, the In/CZO/In device exhibited non-linear and asymmetric I–V curves. Upon exposure to a UV light source of intensity 24 μW/cm2, this non-linearity was found to reduce significantly and a high photosensitivity of 175.9% and responsivity of 110.75 A/W was recorded for the In/CZO/In MSM device. The photoelectrical behavior of the Al/CZO/Al device was found to be consistently ohmic under both dark and illuminated conditions.

Controlled epitaxial growth of GaN nanostructures on sapphire (11–20) using laser molecular beam epitaxy for photodetector applications

We have grown various epitaxial GaN nanostructures on sapphire (11–20) substrates by tuning the buffer layer growth conditions in laser molecular beam epitaxy (LMBE) process. The pre-nitridation and buffer layer GaN growth at low temperature (LT) on sapphire (11–20) critically affect the surface morphology and structural properties. Granular GaN thin film (~ 160 nm) was grown on pre-nitridated sapphire whereas nano-column (NC)-GaN was obtained on LT-GaN buffer layer on bare sapphire having a height of ~ 370 nm at the growth temperature of 700 °C. Nano-porous (NP)-GaN was obtained with pore sizes in the range of 70 ~ 110 nm having vertical height of ~ 560 nm under similar growth conditions on LT-GaN buffered pre-nitridated sapphire. In-situ reflection high energy electron diffraction, high-resolution x-ray diffraction and Raman spectroscopy measurements indicated the epitaxial growth of c-axis oriented, wurtzite crystalline GaN nanostructures on sapphire (11–20) substrate with nearly negligible biaxial stress (0.03–0.23 GPa). Further, metal-semiconductor-metal (MSM) ultra-violet (UV) photodetectors were fabricated on epitaxial GaN nanostructures. The photo responsivity studies revealed that the NP-GaN MSM device has a photoresponse of ~ 358 mA/W at an applied bias of 1V. The photo-responsivity of NP-GaN MSM device is higher than that of GaN film (~ 36 mA/W) and NC-GaN (~7 mA/W) which revealed the importance of shape and size of GaN nanostructures on the responsivity of UV-photodetector devices. These results demonstrate the capability of LMBE technique to grow different GaN nanostructures on sapphire (11–20) substrate by tuning buffer layer conditions for their application as UV-photodetectors.

MoS2, rGO, and CuO Nanocomposite-Based High Performance UV-Visible Dual-Band Photodetectors

This letter reports a Pd/MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /rGO/CuO/ITO structure based Metal-Semiconductor-Metal (MSM) photodetector. The proposed MSM device is obtained by vertical integration of a Pd/MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Schottky junction and a CuO /ITO (i.e., (Indium-doped Tin Oxide) Schottky junction separated by thin reduced graphene oxide (rGO) layer. The rGO layer is used to improve the quality of the MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> layer by mitigating the effects of both the lattice mismatching and van der Waals gap between the MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (Molybdenum disulphide) and CuO (Copper Oxide) layer. The proposed photodetector shows a UV-Visible dual-band photoresponse when the device is illuminated by a monochromatic light intensity of 13.6μ W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at different wavelengths over 300-800 nm. Excellent responsivities and detectivities of 646.8 A/W and 7.28 x 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup> Jones at ~300 nm (in the UV region) and; of 84.32 A/W and 9.6 x 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> Jones at ~498 nm (in the visible region) are measured at 1 V bias voltage, respectively. Also, the device also shows exceptionally high external quantum efficiency (EQE) of 2.6 x 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> % and 3.7 x 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> % at 300 nm and 498 nm, respectively.

Photoresponse properties of coronene nanowires thin-film-based photodiode

The Al/CRNNW/n-Si device with a coronene nanowire (CRNNW) interlayer was fabricated by a physical vapor deposition technique and characterized under dark various illumination intensities via I–V measurements at room temperature. The device has exhibited rectifying behavior and the rectifying ratio values decreased from 1.16 × 103 to 1.44 at 4 V biases by increasing light intensity from 20 to 100 mW. The Al/CRNNW/n-Si device was characterized by various techniques such as thermionic emission theory, Norde, and Cheung technique, and device parameters were obtained. The ideality factor and barrier height values were determined as 21.33 and 0.75 eV, respectively, under dark condition from the thermionic emission theory. The series resistance of the device is obtained as 3090 Ω from the Norde method and 9840 Ω from the Cheung method for the dark condition. The current transport mechanism of the device was discussed in detail for various regions from lnI–lnV plot. The coronene layer can be thought of and improved as interfacial material for metal–semiconductor devices.