Ni Film Thickness Research Articles

Analytical modeling of nucleation and growth of graphene layers on CNT array and its application in field emission of electrons

Carbon Nanotube (CNT) arrays and graphene have undergone several investigations to achieve efficient field emission (FE) owing to CNT’s remarkable large aspect ratio and graphene’s exceptional FE stability. However, when dense CNT arrays and planar graphene layers were used as field emitters, their field enhancement factor reduced dramatically. Therefore, in this paper, we numerically analyze the growth of a dense CNT array with planar graphene layers (PGLs) on top, resulting in a CNT-PGL hybrid and the associated field enhancement factor. The growth of the CNT array is investigated using Plasma Enhanced Chemical Vapor Deposition (PECVD) chamber in C2H2/NH3 environment with variable C2H2 flow, Ni catalyst film thickness, and substrate temperature followed by PGL precipitation on its top at an optimized cooling rate and Ni film thickness. The analytical model developed accounts for the number density of ions and neutrals, various surface elementary processes on catalyst film, CNT array growth, and PGLs precipitation. According to our investigation, the average growth rate of CNTs increases and then decreases with increasing C2H2 flow rate and catalyst film thickness. CNTs grow at a faster rate when the substrate temperature increases. Furthermore, as the chamber temperature is lowered from 750 °C to 250 °C in N2 environment and Ni film thickness grows, the number of the graphene layers increases. The field enhancement factors for the CNT array and hybrid are then calculated based on the optimal parameter values. The average height of the nanotubes, their spacing from one another, and the penetration of the electric field due to graphene coverage are considered while computing the field enhancement factor. It has been found that adding planar graphene layers to densely packed CNTs can raise its field enhancement factor. The results obtained match the current experimental observations quite well.

A fabrication process of soft magnetic Ni films electroplated from gel electrolyte

We have already reported some electroplated magnetic films using aqueous solutions. In the present study, we proposed a fabrication process for electroplated soft magnetic films (Ni films) using gel electrolytes. We added gelatin to the plating baths and confirmed that adding 22 g/L of gelatin enabled us to obtain gel electrolytes. Using the gel electrolytes, we electroplated Ni films and evaluated their structural and magnetic properties. From the evaluation of magnetic properties, we confirmed spontaneous magnetization of the Ni films prepared from the gel electrolyte. For obtaining thick Ni films (>1 μm), we investigated stirring the gel electrolyte during plating. As a result, we found that stirring increased the thickness, and our result suggests that stirring the gel electrolyte is useful to increase the deposition rate. In our experimental conditions, the deposition rate of the plating process was ∼0.25 μm/min. From XRD analysis, the structure of Ni films for gel electrolytes was oriented in the fcc (220) plane and slightly different from that for liquid electrolytes. From these results, we found that soft magnetic films could be obtained from the gel electrolyte and that gel plating is one of the attractive fabrication processes of the thick films.

Direct Characterization of Buried Interfaces in 2D/3D Heterostructures Enabled by GeO2 Release Layer.

Inconsistent interface control in devices based on two-dimensional materials (2DMs) has limited technological maturation. Astounding variability of 2D/three-dimensional (2D/3D) interface properties has been reported, which has been exacerbated by the lack of direct investigations of buried interfaces commonly found in devices. Herein, we demonstrate a new process that enables the assembly and isolation of device-relevant heterostructures for buried interface characterization. This is achieved by implementing a water-soluble substrate (GeO2), which enables deposition of many materials onto the 2DM and subsequent heterostructure release by dissolving the GeO2 substrate. Here, we utilize this novel approach to compare how the chemistry, doping, and strain in monolayer MoS2 heterostructures fabricated by direct deposition vary from those fabricated by transfer techniques to show how interface properties differ with the heterostructure fabrication method. Direct deposition of thick Ni and Ti films is found to react with the monolayer MoS2. These interface reactions convert 50% of MoS2 into intermetallic species, which greatly exceeds the 10% conversion reported previously and 0% observed in transfer-fabricated heterostructures. We also measure notable differences in MoS2 carrier concentration depending on the heterostructure fabrication method. Direct deposition of thick Au, Ni, and Al2O3 films onto MoS2 increases the hole concentration by >1012 cm-2 compared to heterostructures fabricated by transferring MoS2 onto these materials. Thus, we demonstrate a universal method to fabricate 2D/3D heterostructures and expose buried interfaces for direct characterization.

(Second Best Paper Award) Preferred Grain Orientation to Enhance Interdiffusion at Room Temperature in Atomic Diffusion Bonding: A Fundamental Study Using Ni and Cu Films

Atomic diffusion bonding (ADB) of wafers using thin metal films is a promising process to achieve room-temperature wafer bonding [1,2]. During ADB processing, the bonding performance is enhanced by crystal lattice rearrangement, which occurs when two film surfaces mutually contact at room temperature. It is reasonable to infer that the degree of the interdiffusion of the two films at the bonded interface, including crystal lattice rearrangement, depends on the surface roughness and crystallographic grain orientation of the metal films used for bonding. For this study, after Ni film and Cu film were bonded using ADB, the interdiffusion at the bonded Ni/Cu film interface was examined quantitatively using values of saturation magnetization M s. We assessed the effects of crystallographic preferred grain orientation on the interdiffusion thickness at the bonded interface.The Ni film thickness was fixed at 20 nm, but the Cu film thickness was varied from 5 nm to 300 nm. For both films, Ta underlayer films were used. Surface roughness S a, as estimated using AFM of Ni(20 nm) film, was 0.25 nm. The value of S a for Cu films increased from 0.21 nm to 0.85 nm as the Cu film thickness was increased from 5 nm to 300 nm. XRD findings revealed that both Ni and Cu films showed the (111) preferred grain orientation, but the orientation was degraded at Cu thicknesses of less than 50 nm. Figure 1 presents a STEM cross-section image of bonded Ni(20 nm)/Cu(50 nm) films as an example: no vacancy was observed at the bonded interface. Figure 2 presents values of the interdiffusion thickness T ID for bonded films as a function of the Cu film thickness. T IDshowed a maximum of 6.5 nm for a 50-nm-thick Cu film. S a decreased as the Cu thickness decreased from 50 nm. However, T ID decreased remarkably. Results suggest that deterioration of the (111) preferred grain orientation of Cu films with reduction of film thickness degraded the interdiffusion at the Ni/Cu bonded interface.To support this assumption, Ti underlayers were used underneath Ni(20 nm) and Cu(10, 20 nm) films to enhance the degree of the (111) preferred grain orientation of these films. Results indicate that T ID at the Ni(20 nm)/Cu(10 nm) bonded interface was enhanced to 5.4 nm, which was one order greater than that of the bonded films with Ta underlayers, indicating that enhanced bonding performance of ADB can be achieved with low surface roughness and a high degree of (111) preferred grain orientation. This enhancement is expected to be obtained also via ADB processing using other metal films having an fcc crystal structure, such as Au, Ag, and Al. T. Shimatsu and M. Uomoto, J. Vac. Sci. Technol., B 28, 706 (2010).T. Shimatsu and M. Uomoto, ECS Trans., 33 (4), 61 (2010). Figure 1

Insights into the Reaction Energetics and Phase Stability of Electrocatalysts for Upgrading Sustainable Alcohols

The energy efficiency of ambient electrolyzers is currently impacted by oxygen evolution reaction (OER) which not only consumes a significant amount of energy, but also produces oxygen, an intrinsically low value product. When paired with a desired cathodic reaction, such as CO2 conversion to value-added hydrocarbons, it is imperative to choose an anodic reaction that can utilize the energy supplied to the electrolyzer efficiently. Biomass alcohol oxidation has the potential to not only decrease the overall electrolyzer energy input by >50%, but also address critical needs for biomass conversion, another important 21st century non-fossil carbon resource. Here, we present the oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) as an alternative to OER, as this pathway not only decreases the theoretical overall energy input into the electrolyzer, but also produces FDCA, an important biomass-derived chemical building block for the sustainable polyester PEF, a compelling alternative to fossil-based PET which has a global market size of >30 Mt/yr. In this work, we show a synergistic experimental and computational catalysis framework to gain mechanistic insights into the reaction energetics of HMF oxidation on Ni-based catalysts. We experimentally evaluate the redox features of Ni on supports such as Au in a pH range of 10-13 as a function of Ni film thickness (<1-5 nm) to understand the intrinsic kinetics of HMF oxidation and the support effects on the reaction. Computationally, we compare the reaction energetics of OER and hydride transfer reaction of the HMF oxidation to understand the competing pathways on the anode and perform a bulk Pourbaix analysis as a function of strain caused by the presence of the support lattice to understand the phase stability of Ni oxides under oxidizing conditions. This systematic analysis could potentially serve as new guiding principles to design more energy efficient anodes to upgrade sustainable alcohols.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Dual-Band Laser Stealth Based on Quasi Photonic Crystals

A quasi photonic crystal (QPC) dual-band absorber for laser stealth is designed and numerically studied. It consists of a defective two-dimensional photonic crystal on a thick Ni film. The defective photonic crystal is a continuous Ge layer with air holes, but some of the holes are periodically removed. Under a normal incidence that is perpendicular to the plane of the defects, the absorptivity can achieve 92.8% at the 1.064 μm wavelength and 93.2% at the 1.55 μm wavelength. Within large incident angles (&lt;45 degrees), the dual-band absorptivity is still &gt;80%. Additionally, the emissivity is as low as 5.8%~20.0% and 2.8%~5.8% in the 3–5 μm and 8–14 μm atmospheric windows. It is found that the introduced defects can couple the incidence into the structure and lead to spectral peaks (electromagnetic resonances) even without the bottom Ni film. With the help of the high-loss Ni film, the resonances are transformed into magnetic or/and electric modes of different orders. As a result, the QPC generates four absorption peaks. They are superimposed in pairs, resulting in enhanced absorption of the two laser wavelengths.

Application of nano-patterned InGaN fabricated by self-assembled Ni nano-masks in green InGaN/GaN multiple quantum wells

The nano-patterned InGaN film was used in green InGaN/GaN multiple quantum wells (MQWs) structure, to relieve the unpleasantly existing mismatch between high indium content InGaN and GaN, as well as to enhance the light output. The different self-assembled nano-masks were formed on InGaN by annealing thin Ni layers of different thicknesses. Whereafter, the InGaN films were etched into nano-patterned films. Compared with the green MQWs structure grown on untreated InGaN film, which on nano-patterned InGaN had better luminous performance. Among them the MQWs performed best when 3 nm thick Ni film was used as mask, because that optimally balanced the effects of nano-patterned InGaN on the crystal quality and the light output.

Thickness-Controlled Growth of Multilayer Graphene on Ni(111) Using an Approximate Equilibrium Segregation Method for Applications in Spintronic Devices

Thickness-controlled multilayer graphene has been attracting wide interest in electronic and spintronic devices due to its tunable electronic structure and spin transport properties. In particular, the strong spin filtering effect in a lattice-matched Ni(111)/multilayer graphene heterostructure provides an ideal platform for developing high-performance spin valves and magnetic tunnel junctions. However, the thickness-controlled synthesis of multilayer graphene on Ni(111) substrates is still a large challenge, which seriously restricts the development of graphene spintronic devices. Here, we report an approximate equilibrium segregation method for large-area multilayer graphene films on Ni(111) substrates by regulating the growth process of carbon dissolution and segregation. The uniformity and coverage of multilayer graphene films are controlled precisely in an atmospheric tube furnace system by modulating the Ni film thickness, gas atmosphere, and cooling rate. Characterization results systematically confirm the production of high-coverage, high-quality multilayer graphene on Ni(111) substrates. This work provides a reliable method for the controllable fabrication of multilayer graphene on single-crystal ferromagnetic substrates, which would contribute to the application of graphene spintronic devices.

Rapid direct growth of graphene on single-crystalline diamond using nickel as catalyst

Although theoretical investigations indicate that the successful combination of graphene and diamond would give interesting properties, only a limited number of reports dealing with the subject have been published. Here, we present a rapid thermal process (RTP) which involves nickel (Ni) as metal catalyst for a direct growth of graphene on diamond at a temperature of 1073 K for 60 s. This process operates with a combination of a lower temperature and for a shorter duration than what has previously been reported. Thin Ni films of different thicknesses were deposited on top of (100) single-crystalline diamond. After RTP, the coverage of monolayer graphene was found to be around 20% shown by the intensity ratio between the 2D- and G-peak using Raman spectroscopy on 50 nm thick Ni films. In addition, x-ray photoelectron spectroscopy and atomic force microscopy analysis were conducted. For electrical characterization, Hall-effect measurements were performed at temperatures between 80 and 360 K.

Reactive ion etching of ZERO CTE glass for MEMS resonator

In this paper, the reactive ion etching (RIE) of a glass with zero coefficient of thermal expansion (CTE) is reported, which can be used for a high Q-factor resonator used in timing resonators and gyroscopes. ZERO CTE glass can be used for a high Q-factor resonator, which is a key element for gyroscopes. SF6 and Xe were selected as etching gases. A thick Ni film was used as an etching mask. Experimental results show that ZERO CTE glass can be patterned by RIE at an etching rate similar to that of quartz glass. Due to the impurities which were used to control the CTE, the etched surface become rough and the sidewall tilted at about 20 degree. The minimum etching width as small as 30 μm could be achieved.

STRUCTURE, MORPHOLOGY AND MAGNETIC PROPERTIES OF ELECTRODEPOSITED NI FILMS

Ni thin films have been electrodeposited on [Formula: see text]-Si (100) substrates for different deposition times at a fixed potential of 2[Formula: see text]V. The as-elaborated films have been characterized by Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD), atomic force microscopy (AFM) and vibrating sample magnetometry (VSM). From RBS spectra, we have extracted the Ni film thicknesses, [Formula: see text], which ranges from 105 nm to 710 nm. The analysis of XRD spectra shows the existence of a strong [Formula: see text]111[Formula: see text] texture for all film thicknesses. The strain values [Formula: see text] are negative for all Ni films indicating that they are under compressive stresses. The grains size, [Formula: see text], increases to reach a maximum for [Formula: see text][Formula: see text]nm then decreases again with increasing [Formula: see text][Formula: see text](nm). From AFM images, we have shown that the films become progressively smoother with increasing thickness. We have shown that the coercive field measured in parallel geometry, [Formula: see text], increases with increasing thickness.

Growth of low resistive nickel mono-silicide phase under low energy Si ion irradiation at room temperature

Nickel mono-silicide (NiSi) is considered as a promising material for developing low resistance contacts in complementary metal-oxide-semiconductor technology. In the present work, we report the effect of Ni film thickness on orientation control of low resistive Nickel mono-silicide (NiSi) phase formation using low energy ion irradiation at room temperature. In order to study the effect of Ni film thickness on NiSi phase formation, the Ni films of thicknesses 30 nm and 60 nm were deposited on Si (111) substrate using thermal evaporation technique in a high vacuum chamber. The as prepared Ni/Si samples were then irradiated via 120 keV Si ions with different fluences of 7 × 1014, 1 × 1015, 3 × 1015 and 7 × 1015 ions-cm−2 at room temperature. The x-ray diffraction and transmission electron microscopy measurements clearly confirm the formation of mono-silicide phase. The composition of the NiSi phase is determined by Rutherford backscattering spectrometry measurements. The crystallinity of NiSi phase has been observed to be better for 60 nm Ni film as compared to the 30 nm Ni film on Si substrate. Most of the NiSi crystallites are found to be oriented in (103) lattice plane. The resistivity and sheet resistance of the NiSi/Si films are found to be very low. The role of composition of Ni and Si in NiSi phase on resistivity and sheet resistance of the films has been investigated carefully. The detailed mechanisms behind the above observations have been discussed in the paper.

Energy-efficient spin injector into semiconductors driven by elastic waves

Generation of spin imbalance in nonmagnetic semiconductors is crucial for the functioning of many spintronic devices. An attractive design of spin injectors into semiconductors is based on a spin pumping from a precessing ferromagnet, typically excited by a microwave magnetic field leading to a high power consumption of the device. Here we describe theoretically a spin injector with greatly reduced energy losses, in which the magnetic dynamics is excited by an elastic wave injected into a ferromagnet-semiconductor heterostructure. To demonstrate the efficient functioning of such an injector, we perform micromagnetoelastic simulations of the coupled elastic and magnetic dynamics in Ni films and Ni/GaAs bilayers. For thick Ni films, it is shown that a monochromatic acoustic wave generates a spin wave with the same frequency and wavelength, which propagates over distances of several micrometers at the excitation frequencies close to the frequency of ferromagnetic resonance. The simulations of Ni/GaAs bilayers with Ni thicknesses comparable to the wavelength of the injected acoustic wave demonstrate the development of a steady-state magnetization precession at the Ni/GaAs interface. The amplitude of such a precession has a maximum at Ni thickness amounting to three quarters of the wavelength of the elastic wave, which is explained by an analytical model. Using simulation data obtained for the magnetization precession at the Ni/GaAs interface, we evaluate the spin current pumped into GaAs and calculate the spin accumulation in it by solving the spin diffusion equation. Then the electrical signals resulting from the spin flow and the inverse spin Hall effect are determined via the numerical solution of the Laplace's equation. It is shown that amplitudes of these ac signals are large enough for experimental measurement, which indicates an efficient acoustically driven spin pumping into GaAs.

Synthesis of uniform nanometer-thick graphite film on polycrystalline Ni substrate with ultrafine grains

When a polycrystalline Ni foil is used as the substrate for the chemical vapor deposition synthesis of multilayer-graphene or nanometer-thick graphite films (NGFs), these films always exhibit uneven morphologies and qualities on Ni grains with different orientations. In this study, we fabricated a carbon-supersaturated Ni foil (ss-Ni foil) to function as a carbon source through an ultrafast cooling process (∼180 °C/s), while an additional Ni film was sputtered on the ss-Ni foil to act as a buffer layer and a new surface for NGF growth. By re-annealing the Ni film/ss-Ni foil system at a low temperature (∼650–800 °C) within a short duration, NGF can rapidly form on the Ni film owing to the high supersaturation degree of the ss-Ni foil. The grain growth of the Ni film is limited by the low-temperature growth process, and the ultrafine grains of Ni film averaged the grain orientation effect from the Ni foil. The NGF formed on the Ni film/ss-Ni foil showed a significant improvement in thickness and quality uniformity, and we studied the influences of Ni film thickness as well as re-annealing temperature and time on the diffusion of carbon in the Ni film/ss-Ni foil system and summarized the growth mechanism.

Effect of the thickness of nickel film interlayer on direct‐bonded aluminum/alumina as substrate in high‐power devices

AbstractAluminum (Al) was successfully bonded with alumina (Al2O3) using Ni films of different thicknesses (3, 6, 12 μm) through electroplating and electroless plating processes after annealing at the relatively low melting point of Al. The microstructure, bonding area percentage, shear strength, and thermal conductivity of Al/Al2O3 joints were evaluated using scanning electron microscopy, scanning acoustic tomography (SAT), the ISO 13124 test, and the laser flash method respectively. No reaction layer was found at the interface of the Al/Al2O3 joint, and the Ni film diffused completely into Al to form an intermetallic compound, Al3Ni, in the Al foil. The amount and size of the Al3Ni phase in the Al foil increased gradually with the thickness of the Ni film. The samples with Ni deposited via electroplating had a higher shear stress and bonding area than the samples with Ni deposited via electroless plating. The Al/Al2O3 specimen with a 3‐μm‐thick Ni film interlayer deposited using electroplating had the highest shear strength (50.6 MPa), thermal conductivity (39.45 W/mK), and bonding area percentage (~99.97%); therefore, specimens produced under these conditions were considered suitable for use as a substrate in high‐power devices.

Nickel thin film preparation and its characterization as catalyst for HWC-in plasma-PECVD-growth graphene

Nickel thin film, aimed at catalyst layer for HWC-in plasma-PECVD-growth of graphene, has been deposited on SiO2 glass of microscope slide by thermal evaporation method. The thickness of the as-deposited Ni films was not uniform ranging from 200 nm to 700 nm as revealed from cross sectional SEM image. To reduce the film thickness and improve the crystal quality of the films, the samples were annealed in the furnace with three different temperatures, T = 400 °C, 500 °C, and 600 °C, for three hours. SEM images of the post-treatment indicated that the film thickness decreased to about 100–200 nm after annealed at 500 °C for 3 h. Increasing the annealing temperature to 600 °C leads the nickel atoms out of the substrate so that it leaves the substrate without nickel thin film anymore. The disappearing of the Nickel film after annealing at temperature 600 °C was confirmed by EDS spectrum examination which showed that there was no nickel element in the sample. Due to the loss of nickel thin film after annealing at 600 °C, we set the annealing temperature at 500 °C and optimized duration of annealing. It was found that after annealing for 4 h the obtained thickness of thin film was averagely 44 ± 6 nm with some spread piles on the film. Increasing annealing duration to 5 h lead to increasing the thickness of thin film nickel to be 66 ± 14 nm which seems contradict with our expectation. However, the tens order magnitude of thin film thickness obtained is the expected result for graphene growth.

Thermal Silicidation of Ni/SiGe and Characterization of Resulting Nickel Germanosilicides

Thermal silicidation characteristics of Ni/Si1-xGex with various Ge content was studied under different annealing temperatures in the range of 225 °C ∼ 400 °C in 100% N2 ambient. TiN capped Ni/Si1-xGex/Si/SiO2/Si wafers with x values in the range of 0.15 and 0.30 in 0.05 intervals were used. Thermal silicide formation was performed in a stacked hotplate-based annealing system designed for industrial 300 mm wafer fabs. For silicide characterization, measurements of spectral reflectance, sheet resistance, Raman spectra as well as X-ray diffraction curves were performed to investigate changes of optical properties, electrical properties, crystallographic phases during silicide formation. Effects of Ge content and annealing temperature on the electrical and crystallographic properties of the resulting thermal silicides (nickel germanosilicides) were investigated. Reaction mechanisms were discussed based on the characterization results. Multiwavelingth micro-Raman spectroscopy was found to be very promising as a non-contact, in-line silicidation process monitoring technique. For production worthiness verification of the thermal silicidation process, temperature sensitivity curves of sheet resistance, its uniformity and detailed sheet resistance maps were investigated using 8 nm thick Ni films on 300 mm diameter, epitaxial Si0.8Ge0.2/p−-Si wafers without a capping layer. Manufacturability of Ni/Si0.80Ge0.20/Si wafers were also verified using a stacked hotplate-based, nearly isothermal, annealing system.

Rapid growth of large area graphene on glass from olive oil by laser irradiation

Although homogeneous, high quality graphene can be fabricated on a Cu or Ni sheet using the traditional chemical vapour deposition method at high temperatures (over 1000 °C) under specific atmospheric conditions, their transfer to another substrate is difficult. In this paper a novel method of rapidly (i.e. 3–6 s of laser irradiation) producing a large area (>3 cm2) graphene film from olive oil on a glass surface (pre-coated with a 5–28 nm thick Ni film) with defocused, large area continuous laser irradiation is described. The turbostratic graphene film (6 layers) grown in such a way has shown high electrical conductivity (sheet resistance of around 20 Ω sq−1) and an optical transmittance of 40–50%. With femtosecond laser patterning, 70% optical transparency was demonstrated. Continuous large area graphene was formed at relatively lower temperatures (<250 °C) and without the need for specific atmospheric conditions. The basic process characteristics and mechanisms involved are discussed.

Ultra-thin and conformal epitaxial NiSi2 film on Si fins by barrier-induced phase modulation (BPM) technique

In this work, a barrier-induced phase modulation scheme to realize an ultra-thin and conformal epitaxial NiSi2 film for wrapped-around contact beyond the 7 nm technology node, is proposed and experimentally demonstrated. The 1 nm thick Al2O3 barrier inserted between the Ni film and the substrate can limit the amount of nickel diffusing into silicon and establish an initial Si-rich region consisted of only a few atomic layers during a rapid thermal annealing treatment, so that NiSi2 can grow epitaxially as the first phase at a temperature as low as 600 °C. Additionally, thanks to the barrier layer, a relatively thick (50 nm) Ni film can be used, which not only ensures the continuity of NiSi2 formed on sidewalls of three-dimensional structures, but also reduces the process complexity. As a result, a conformal 3.3 nm NiSi2 shell with ΦBn = 0.33 eV is successfully obtained on Si fins.

Surface Plasmon‐Enhanced High‐Performance ZnO/Ni/ZnO Ultraviolet Photodetectors

The surface plasmon effect of Ni thickness on the optical and electrical properties of ZnO/Ni/ZnO multilayer structure (MS) ultraviolet photodetectors (PDs) is investigated. In general, ZnO/Ni/ZnO MS can be used as a transparent conductive oxide. As the thickness of the Ni thin interlayer increases from 0 to 8 nm, the optical transmittance of the ZnO/Ni/ZnO MS‐PDs decreases from 90.9% to 54.4%. The optical absorptions of the Ni/ZnO and ZnO/Ni/ZnO MS films increase with a 2.0 nm‐thick Ni film. In addition, despite depositing a Ni film on ZnO, the maximum photoluminescence (PL) intensity is obtained from the 2.0 nm‐thick Ni on the ZnO film. However, the optical absorption and PL band‐edge emission of ZnO/Ni/ZnO MS‐PDs decrease gradually with increasing Ni film thickness (&gt;2.0 nm). Thus, this optical improvement of ZnO/Ni/ZnO can be caused by the surface plasmon effect, which leads to an increase in the number of photogenerated carriers in ZnO/Ni/ZnO MS‐PDs. Therefore, the higher photoresponsivity (19.5 mA W−1) and external quantum efficiency (6.5%) of the ZnO/Ni/ZnO MS‐PDs are achieved with a 2.0 nm‐thick Ni interlayer compared with ZnO single‐layer PDs.