Telluride Thin Films Research Articles

FABRICATION AND CHARACTERIZATION OF BISMUTH TELLURIDE THIN FILMS BY THERMAL EVAPORATION TECHNIQUE

An interest in the study of the structural and optical properties of topological insulators, led to the selection of Bismuth telluride thin films. Among the topological insulators, Bismuth telluride is one of the promising materials that exhibit applications in the field of thermoelectric power generation. The films were prepared using the thermal evaporation method under vacuum conditions of [Formula: see text] mbar on glass substrates maintained at a temperature of 120∘C. The thickness of the film samples ranges from 400 Å to 1400 Å. Pure phases of Bi2Te3 with a rhombohedral structure are confirmed using X-ray Diffraction. The crystallite size was calculated using Debye–Scherrer’s formula. Structural morphology and compositions are examined using SEM and EDAX. The UV–Vis study reflects the optical behavior of the thin film samples. The absorption spectra gives the direct and allowed transition band gap of the Bi2Te3 thin film samples for various thicknesses. The band gap decreases with the increase in the thickness of the Bi2Te3 thin films, suggesting that the material has significant absorption towards the visible spectrum. The Photoluminescence (PL) emissions for Bi2Te3 thin film samples of various thicknesses are examined and analysed. Raman study reveals the presence of two active modes.

Particle swarm optimization for performance enhancement of cadmium telluride thin film solar cells by embedded nano-grating structures with a plasmonic metal coating layer

As the demand for energy in world is increasing rapidly and there is pursuit for renewable energy sources which is cheap, easy to generate and requires low maintenance, solar energy is a top contender. The world is in dire need of photovoltaic solar cells that can aid in keeping up with the hiking energy demands. However, thin film solar cells (TFSCs) which are developed for cost effectivity, suffer in performance due to reduced thickness. Therefore, this computational study uses Finite-Difference Time-Domain (FDTD) and delves into the scope of using a 1-D nano-grating structure embedded into absorbing layer of cadmium telluride TFSC to enhance the optoelectronic performance. A unique nano-grating structure with SiO2 at its core and aluminium coating aims to enhance the performance of CdTe TFSC with cost effectivity and ease of fabricability as the main motifs. Additionally, an evolutionary computational technique, Particle Swarm Optimization (PSO), was used to determine the optimal parameters of nano-gratings on CdTe TFSCs, i.e., nano-grating height, angle, duty cycle, aluminium coating thickness and grating substrate thickness. The PSO algorithm resulted in a nano-grating structure that yielded an efficiency increase of 52.86% and increase in short-circuit current density of 25.45% with respect to bare CdTe TFSCs. Subsequently, the performance of the optimal nano-grating structure was also observed to be insensitive to variation of wide range of incidence angle of light, a key feature preferred for versatile application of TFSCs.

Self-aligned shadow masking for antimony telluride growth: Novel advancements in single-leg thermoelectric array design

In the present study, a fabrication technique using self-aligned shadow masking was employed to create a state-of-art thermoelectric single-leg array of Antimony telluride (Sb2Te3) thin film via thermal evaporation technique. The thermoelectric (TE) performance of the array was evaluated using an in-house developed measurement setup. The TE characteristics of the developed p-type Sb2Te3 based TEGs with single-leg configurations, having 5-TE legs, exhibits a highest Power factor (PF) of ∼5173 μW/mK2 at RT along with thermoelectric voltage generation of 70 mV. As compared to planar configuration these segmented single-leg array-based TEG of Sb2Te3 exhibit higher efficiency (∼10 %) under a near-ambient temperature gradient. Also, the 3ω-method is utilized to assess the thermal conductivity of fabricated thin films of Sb2Te3, yielding a value of 0.41 Wm⁻1K⁻1. Furthermore, these thermoelectric generators (TEGs) showcase their versatility across various applications, efficiently harnessing near-room temperature waste heat from a range of sources such as tea coasters, the human body, and gas cookstoves into useable energy near room temperature.

Flexo-photovoltaic effect in strained bismuth telluride thin films without substrate bending under light irradiation

Bismuth telluride (Bi2Te3) is gaining increasing attention as a material that exhibits flexo-photovoltaic effect in the infrared region, in addition to conventional thermoelectric materials and topological insulators. However, the flexo-photovoltaic effect is observed only when strains are applied to the Bi2Te3 thin films by bending the substrates. To enhance the versatility of the flexo-photovoltaic effect, in this study, Bi2Te3 thin films were sputtered onto a flexible substrate under a pre-curved condition, and strains were induced when the films were flattened. The crystal orientation and strains in the Bi2Te3 thin films were affected by the pre-curved conditions. The Bi2Te3 thin film deposited using a concave pre-curved condition exhibited an output voltage increase of approximately 15 % compared with the film deposited under a flat condition. This discovery suggests that strained Bi2Te3 thin films can efficiently produce an output voltage under light irradiation without requiring a p–n junction, making them suitable for various photodetector applications.

Fabrication of Bi2Te3 and Sb2Te3 Thermoelectric Thin Films using Radio Frequency Magnetron Sputtering Technique.

Through various studies on thermoelectric (TE) materials, thin film configuration gives superior advantages over conventional bulk TEs, including adaptability to curved and flexible substrates. Several different thin film deposition methods have been explored, yet magnetron sputtering is still favorable due to its high deposition efficiency and scalability. Therefore, this study aims to fabricate a bismuth telluride (Bi2Te3) and antimony telluride (Sb2Te3) thin film via the radio frequency (RF) magnetron sputtering method. The thin films were deposited on soda lime glass substrates at ambient temperature. The substrates were first washed using water and soap, ultrasonically cleaned with methanol, acetone, ethanol, and deionized water for 10 min, dried with nitrogen gas and hot plate, and finally treated under UV ozone for 10 min to remove residues before the coating process. A sputter target of Bi2Te3 and Sb2Te3 with Argon gas was used, and pre-sputtering was done to clean the target's surface. Then, a few clean substrates were loaded into the sputtering chamber, and the chamber was vacuumed until the pressure reached 2 x 10-5 Torr. The thin films were deposited for 60 min with Argon flow of 4 sccm and RF power at 75 W and 30 W for Bi2Te3 and Sb2Te3, respectively. This method resulted in highly uniform n-type Bi2Te3 and p-type Sb2Te3 thin films.

Structural, optical, and electrical analysis of tailoring Bi2-xSbxTe3 thin films

Bismuth antimony telluride (Bi2-xSbxTe3) thin films were synthesized using chemical bath deposition (CBD) with various amounts of antimony. The structural, morphological, and optical properties of Bi2-xSbxTe3 thin films have been scrutinized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), UV-Vis spectrophotometry. A higher amount of Sb contents can be observed the Sb0.405Te0.595, BiTe, and Bi4Te3 phases consisted in the pattern. Meanwhile, the energy band gaps are tuned in the range of 2.95 to 3.30 eV. Finally, measurement of resistance with various temperatures for activation energy (EAC) estimation was performed. The highest EAC value was equal to 0.654 eV for 0.8 g SbCl3 as a precursor of Sb atom incorporated in the Bi2Te3 lattice.

Effect of Deposition Working Power on Physical Properties of RF-Sputtered CdTe Thin Films for Photovoltaic Applications.

The main objective of this study was to determine the variation in the properties of cadmium telluride (CdTe) thin films deposited on a p-type Si substrate by the radio frequency magnetron sputtering technique at four different working powers (70 W, 80 W, 90 W, and 100 W). The substrate temperature, working pressure, and deposition time during the deposition process were kept constant at 220 °C, 0.46 Pa, and 30 min, respectively. To study the structural, morphological, and optical properties of the CdTe films grown under the mentioned experimental conditions, X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and optical spectroscopy were used. For a better analysis of the films' structural and optical properties, a group of films were deposited onto optical glass substrates under similar deposition conditions. The electrical characterisation of Ag/CdTe/Al "sandwich" structures was also performed using current-voltage characteristics in the dark at different temperatures. The electrical measurements allowed the identification of charge transport mechanisms through the structure. New relevant information released by the present study points towards 90 W RF power as the optimum for obtaining a high crystallinity of ~1 μm nanostructured thin films deposited onto p-Si and optical glass substrates with optical and electrical properties that are suitable for use as absorber layers. The obtained high-quality CdTe nanostructured thin films are perfectly suitable for use as absorbers in CdTe thin-film photovoltaic cells.

Etching and Compositional Ratio Effect on the Surface Properties of Bismuth Telluride Thin Films

Bismuth telluride has garnered considerable attention owing to its versatile properties applicable in thermoelectric and antibacterial domains, as well as its intriguing topological insulating properties. In this work, our group fabricated bismuth telluride thin films with various ratios using radio frequency magnetron sputtering. The surface properties of these thin films were thoroughly analyzed by employing a diverse array of analytical techniques, including X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), four-point probe and contact angle (CA) measurements. Specifically, our XPS findings indicated that Bi is more susceptible to oxidation than Te following Ar+-ion etching. Pure Te thin films exhibited the highest Rq value of 31.2 nm based on AFM and SEM results due to their larger grain sizes. The XRD patterns revealed a peak at 27.75° for thin films with 20% Te, attributed to its rhombohedral structure. Moreover, thin films with 30% Te yielded the highest weighted average work function with a value of 4.95 eV after etching. Additionally, pristine Bi and Te thin films demonstrated the most robust hydrophobic properties compared to intermediate-composition thin films, as determined by CA measurements.

Investigation of the Effects of Different H2SO4, HCI, HNO3 and HCIO4 Liquid Acid Media on the Synthesis of CdTe Semiconductor Thin Films for Solar Cells

The main target of the present paper is to investigate the effect of different acidic aqueous media(DAAM) on the synthesis of cadmium telluride thin films(CdTeTFm). The synthesis of CdTeTFm was carried out by the electrochemical deposition method(EDM) in DAAM. The chronoamperometry method of electrodeposition(ED) was used for the production of CdTeTFm. Furthermore, the electrochemical behaviors of the solutions were studied using cyclic voltammetry. The experiments were carried out with 3 electrodes (a working electrode (WE), a reference electrode(CE), and a counter electrode(RE)) using the electrochemical cell potentiostatic method. The experimental conditions of the acidic aqueous CdTe solution have been determined to be pH 3.56-3.57, the temperature of the solution is 85°C, the concentration of CdTe 2.45x10-1 M, and the reaction time is 25 minutes. The physical properties of CdTeTFm were determined by XRD, SEM/EDX, FT-IR, and UV-VIS analysis methods. According to the results of the analysis, it was observed that acidic aqueous media have an important role in the synthesis of CdTeTFm. The bandgap ranges and Cd/Te ratios of the synthesized thin films were obtained as 1.42, 1.48, 1.50, 1.58 eV, 0.65, 0.587, 0.79 and 0.738, respectively.

Prospects of Taiwan's solar energy development and policy formulation

Taiwan lacks energy stock and has been paying great attention to developing renewable energy to improve energy security and sustain economic growth. Solar energy is attractive to Taiwan's government as the recorded radiation is substantial, and a significant amount of fallow land is available for panel installation. This study investigates the potential solar energy production from Crystalline silicon (c-Si) and cadmium Telluride thin-film (CdTe) cell systems, estimates each system's capital requirement, and compares the economic and environmental benefits to explore effective investment strategy. The results show that, on average, the c-Si module could produce 10,644 GWh per year while the CdTe mode would yield a total electricity of about 9365 GWh. The useful life also plays an essential role in the investment requirement. With a 30-year useful life, the systems can reduce the annualized installation and maintenance cost to about NT$3.16 billion. In terms of offset efficiency, every MWh produced would result in at least 13.63–15.49 metric ton of carbon emission offset, and the offset value per GWh can be up to NT$5.77 million, which provide attractive economic incentives to energy suppliers. We point out that the acquisition of low-cost financing sources such as green bonds, as well as the improvement of current emission trading systems (ETS), would greatly benefit solar energy development.

Low resistance large area terahertz detector based on antimony telluride thin film

Terahertz technology has great potential for various applications in fields like biomedicine, astronomy, communications, and security inspection. Therefore, terahertz detectors that can operate at room temperature with fast response times, high sensitivity, wide detection bandwidth, and can be seamlessly integrated. To achieve this, a metal–semiconductor-metal structure with a subwavelength gap is used, which creates an electromagnetic induced potential well within the semiconductor by utilizing the antisymmetric electric field of terahertz radiation. This structure allows for the injection and retention of electrons from the metal, enhancing electrical conductivity. Experimental results have shown that reducing the spacing between the forked finger electrodes improves the detection performance of the device. At room temperature, with a bias voltage of 1 V and 0.28 THz radiation, the device achieves an equivalent noise power of 9.76 × 10−13 W/Hz/2 and a detection rate of 2.41 × 1011cm Hz1/2W−1. Additionally, the device's simple structure and large effective detection area make it suitable for producing low-resistance and large-area terahertz detectors.

Controllable phase transition of two-dimensional ferromagnetic chromium telluride thin films grown by molecular beam epitaxy

Two-dimensional (2D) Cr(1+δ)Te2 materials exhibit strong magnetic ordering and high Curie temperatures, making them attractive for various applications. It is crucial to achieve controllable synthesis for their successful integration into device technologies. In this study, we present the synthesis of phase-controllable 2D Cr(1+δ)Te2 films on the Si (111) substrate via molecular beam epitaxy. The composition and phase transition of the as-grown Cr(1+δ)Te2 films are characterized by using in-situ reflection high-energy electron diffraction, scanning tunneling microscopy, ex-situ X-ray photoelectron spectroscopy, X-ray diffraction, and theoretical calculations. At low growth temperatures, by carefully adjusting the film thickness from 2 to more than 3 layers, we achieve precise control over the phase of Cr(1+δ)Te2, from CrTe2 to Cr intercalated Cr2Te3. At a relatively elevated growth temperature, it is demonstrated that the Cr(1+δ)Te2 phase is independent of the film thickness, only Cr2Te3 forms and its growth mode is thickness-dependent. These phase transitions at low growth temperatures and growth mode changes at elevated growth temperatures are attributed to interfacial effects and the phase stability of Cr(1+δ)Te2 compounds. Additionally, we utilize scanning tunneling spectroscopy and computations to gain insights into the electronic properties of Cr2Te3. The magnetic measurements reveal that the 30-nm Cr2Te3 film exhibits ferromagnetic behavior with a Curie temperature of about 180 K. Our work offers a robust method for the controllable growth of high-quality 2D Cr(1+δ)Te2 films on Si substrates, providing an ideal platform for investigating their intrinsic properties and advancing the development of 2D magnet-based spintronics devices.

Lattice mismatch alleviation in p-CdTe/n-Si heterostructure by surface engineering on Si substrate

The study used magnetron sputtering to investigate the growth of cadmium telluride (CdTe) thin films on surface treated n-type silicon (n-Si) substrates. The n-Si substrates were textured using potassium hydroxide (KOH) before the sputter deposition of CdTe. This was followed by cadmium chloride treatment to reduce the strain at the interface of CdTe and Si, which is caused by the incompatible lattice and thermal expansion mismatch (CTE). X-ray diffraction (XRD) analysis showed that the lowest FWHM and dislocation densities were obtained for CdCl2/CdTe/txt-nSi, which aligns with the scanning electron microscopy (SEM) results. In the SEM images, the interface bonding between the CdTe and Si surfaces was visible in the cross-sections, and the top-view images revealed sputtered CdTe thin films conforming to the patterns of pyramidal textured Si as an engineered surface to capture more light to maximize absorption in the CdTe/Si tandem design. The Energy dispersive X-ray (EDX) results showed that all the CdTe deposited on textured n-Si exhibited more Te atoms than Cd atoms, irrespective of the CdCl2 treatment. The presented results suggest that the texturization and CdCl2 treatment improved the morphology and grain boundary passivation of the sputtered CdTe. The adhesiveness of CdTe on the n-Si substrate was also significantly enhanced. Our findings further demonstrate that proper surface treatment of the Si substrate can greatly improve the quality of CdTe grown on Si by reducing the strain that occurs during the growth process. This study demonstrates a valuable method for enhancing the integration of CdTe with Si for two-junction tandem solar cell applications.

Low-Temperature ALD of SbOx /Sb2 Te3 Multilayers with Boosted Thermoelectric Performance.

Nanoscale superlattice (SL) structures have proven to be effective in enhancing the thermoelectric (TE) properties of thin films. Herein, the main phase of antimony telluride (Sb2 Te3 ) thin film with sub-nanometer layers of antimony oxide (SbOx ) is synthesized via atomic layer deposition (ALD) at a low temperature of 80 °C. The SL structure is tailored by varying the cycle numbers of Sb2 Te3 and SbOx . A remarkable power factor of 520.8 µW m-1 K-2 is attained at room temperature when the cycle ratio of SbOx and Sb2 Te3 is set at 1:1000 (i.e., SO:ST = 1:1000), corresponding to the highest electrical conductivity of 339.8 S cm-1 . The results indicate that at the largest thickness, corresponding to ten ALD cycles, the SbOx layers act as a potential barrier that filters out the low-energy charge carriers from contributing to the overall electrical conductivity. In addition to enhancing the scattering of the mid-to-long-wavelength at the SbOx /Sb2 Te3 interface, the presence of the SbOx sub-layer induces the confinement effect and strain forces in the Sb2 Te3 thin film, thereby effectively enhancing the Seebeck coefficient and reducing the thermal conductivity. These findings provide a new perspective on the design of SL-structured TE materials and devices.

N-type CdTe:In for photovoltaics: in situ doping, type verification and compensation effects

We explored the in-situ doping of cadmium telluride thin films with indium to produce n-type absorbers as an alternative to the near-universal choice of p-type for photovoltaic devices. The films were grown by close space sublimation from melt-synthesised feedstock. Transfer of the indium during film growth was limited to 0.0014%–0.014%—unless reducing conditions were used which yielded 14%–28% efficient transport. While chunks of bulk feedstock were verified as n-type by the hot probe method, carrier type of thin film material was only able to be verified by using hard x-ray photoelectron spectroscopy to determine the Fermi level position within the band gap. The assignment of n-type conductivity was consistent with the rectification behaviour of a p-InP/CdTe:In junction. However, chloride treatment had the effect of compensating n-CdTe:In to near-intrinsic levels. Without chloride, the highest dopant activation was 20% of the chemical concentration of indium, this being for a film having a carrier concentration of n = 2 × 1015 cm−3. However, the activation was often much lower, and compensation due to over-doping with indium and native defects (stoichiometry) are discussed. Results from preliminary bifacial devices comprising Au/P3HT/ZnTe/CdTe:In/CdS/FTO/glass are presented.

Fabrication and optical characterization of zinc telluride thin films using electrodeposition technique

A well adherent thin film of Zinc Telluride (ZnTe) has been deposited on Flourine doped Tin oxide glass substrates from acidic baths containing Zinc heptahydrate and Tellurium dioxide. Films of different thicknesses with their molar concentrations were obtained. A mini Schimadzu UV-VIS Spectrophotometer was used to determine the optical absorbance of the films over the wavelength range of 300-900nm at room temperature. There is a decrease in absorbance as the molar concentrations of the precursors increases; while transmittance and energy band gap shown an increase. The band gap values obtained varied between 2.10eV and 2.7eV, for as deposited films. Also, photoelectrochemical cell (PEC) measurement reveals that ZnTe thin films exhibit p-type conductivity.

Effect of pulsed hydrogen and helium plasma irradiation on the formation of solid solutions in the thin-film CdTe/CdS heterosystem

The interphase interaction of cadmium sulfide and cadmium telluride thin film layers under irradiation with pulses of hydrogen and helium plasma was investigated by the X-ray diffraction method. CdS/CdTe heterosystem samples were obtained by the hot wall method on glass substrates with a transparent FTO electrode. During deposition of CdS layers 0.3–0.32 µm thick, the temperature of the evaporator zone was 590 °C, and the substrate temperature was 395 °C. CdTe layers 3.8–4.0 µm thick were deposited at an evaporation zone temperature of 520 °C and a substrate temperature of 497 °C. After deposition, the “chloride” treatment of the heterosystem was carried out. The “chloride” treatment consisted in the deposition of a cadmium chloride film 0.7 μm thick on the surface of a CdTe by thermal vacuum evaporation without heating the substrate and by annealing the entire structure in air at a temperature of 410-415 °C for 20 min. The composition of the solid solutions was determined from the lattice period according to Vegard's rule. In the initial state, along with the cubic phase of cadmium telluride, the presence of CdTe1-xSx solid solutions with a sulfur concentration of 3 % and 8.2 % is observed. After irradiation of the CdS/CdTe heterosystems with hydrogen plasma pulses, the entire base layer turned into a solid solution with a sulfur concentration of 3 %. At the same time, two more phases of CdTe1-xSx solid solutions with sulfur concentrations of 6 % and 11.5 % were observed. The relative concentration of the cadmium telluride phase in the initial state was 84 %, after irradiation with hydrogen plasma pulses it was 82 %. In the initial state, the phases of solid solutions with sulfur content of 3 % and 8.2 % had relative concentrations of 7 % and 9 %, respectively; after irradiation, their relative concentrations became 15 % and 3 %, respectively. After irradiation of the CdS/CdTe heterosystem with helium plasma pulses, the entire base layer turned into a solid solution with a sulfur concentration of 1.5 %. In this case, two more phases with a sulfur concentration of 3.7 % and 7.9 % were observed. The relative concentration of cadmium phase telluride after irradiation with hydrogen plasma pulses decreases to 79 %. After irradiation, the relative concentration of the phase of solid solutions with sulfur contents of 3 % and 8.2 % increases to 17 % and 12 %, respectively. The experimentally observed difference in the evolution of the phase composition of the CdS/CdTe film heterosystem under irradiation with hydrogen and helium plasma pulses may be due to the fact that irradiation with more massive helium atoms leads to a greater thermal effect, which causes melting.

Fabrication and investigation of zinc telluride thin films

Zinc Telluride ZnTe alloys and thin film have been fabricated and deposited on glass substrates by thermal evaporation method which may be a suitable window layer of zinc telluride with different annealing temperatures (373 and473) K for 60 minutes in vacuum. Deposited thin films with thickness 100 nm was characteristic by using X-ray diffraction XRD to know structures, Atomic Force Microscopy (AFM) to evaluate surface topology, morphology. It was found out that the vacuum annealing improves on thin ZnTe films structure and surface morphology. Structural analysis reveals that ZnTe films have zinc blende structure of cubic phase with (111) preferred reflection and grain size is enhanced from 8.6 to 16.7 nm with annealing. Optical properties where optical bandgap energy values slightly decreased (2.3-2.2) eV as the annealing temperatures.

Structural and optical properties of smooth radio frequency sputtered XTe (X=Cd, Zn) thin films

Zinc telluride (ZnTe) and cadmium telluride (CdTe) thin films, with smooth surfaces, were prepared by the radio frequency sputtering method. X-ray diffaction patterns revealed the formation of pure cubic phases and allowed the access of the structural properties. The lattice mismash between the two compounds is found to be around 6%.UV–visible spectroscopy showed a significant absorption coefficient within the visible spectrum, accompanied by an energy band gap measuring 1.9 eVfor the ZnTe film and 1.42 eV for the CdTe film. This study may be benificial for using these materials together of separately in photovoltaic and photocatalytic devices.

Enhanced physical properties of nickel telluride metal chalcogenide material with molybdenum dopant

ABSTRACT In the study, nickel telluride and molybdenum dopants were synthesised using an electrochemical deposition approach. The nanoparticle of the material shows the reaction between the transition metal and chalcogenide material, and the nickel telluride pristine demonstrates that the film surface provides a clean image of melted wax with splattered evidence of oil on the film. The film that was deposited at 0.1 mol% clearly shows how the dopant changed the melted wax to nanoparticles, demonstrating the compatibility of the two materials. The structural patterns showed diffraction peaks at the (111), (200), (210), (211), (300), and (311) diffraction planes, which are equivalent to 13.22 °, 16.95 °, 18.85 °, 25.93 °, 30.84 °, and 32.98 ° for nickel telluride and 13.38 °, 16.93 °, 19.02 °, 25.95 °, 30.85, and 33.02 ° for molybdenum-doped nickel telluride. Both nickel telluride and molybdenum-doped nickel telluride materials produced similar peaks. When the dopant was added, the thickness of the molybdenum-doped nickel telluride films grew from 132.02 to 147.57 nm. The UV area of the spectra was found to have the maximum absorbance and reflectance, however, the transmittance increased as the wavelength of the incident radiation increased. The absorbance, transmittance, and reflectance of nickel telluride and molybdenum-doped nickel telluride thin film material are improved by the addition of molybdenum as a dopant. The energy bandgap of the synthesised films; the nickel telluride has 1.18 eV, while the doped nickel telluride has an energy bandgap of 1.50–1.55 eV which shows that the energy bandgap narrows as molybdenum-dopant concentration rises.