Growth of CuAlTe2 films by RF sputtering (original) (raw)
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Effect of substrate temperature on the crystalline phases of Cu 2-x Te films grown by RF sputtering
Physica B: Physics of Condensed Matter, 2022
The effect of the substrate temperature (Ts) on the growth of Cu 2-x Te films using the RF sputtering technique has been studied through a structural assessment of the different trigonal (space group P3m1) phases encountered in the range 100-350 • C. A new stoichiometric Cu 7 Te 4 phase (δ ′) with Z = 1 is proposed, and it is present in all the temperatures studied. Low-angle peaks (2θ < 20 •) of Glancing Incidence X-ray Diffraction (GIXD) patterns are consistent with the formation of commensurate phases (forms α ′) through variations in the c parameter whose value can be as large as 25.47 Å. The base modulation vector is the c parameter of the unit-cell of phase δ ′ that, in this work, resulted in a value of 3.61 Å. The origin of the observed commensurate phases has been ascribed to an occupancy-wave modulation. Whereas at high temperatures (Ts > 250 • C), the major phase is δ' (Cu 7 Te 4 or Cu 2x Te with x = 0.25), the predominant phase, for Ts < 250 • C, is the commensurate superstructure 7C with higher [Cu]/[Te] ratio (x < 0.25). The transition between these two thermal regimes is stated at a temperature of about 250 • C. Maintaining a constant global composition, the devaluation of [Cu] in films, with the temperature above the transition range, is explained in terms of diffusion of copper downward the film and towards its edges.
Direct preparation of crystalline CuInS2 thin films by radiofrequency sputtering
Materials Science and Engineering: B, 2009
Crystalline chalcopyrite CuInS 2 thin films were obtained by r.f. sputtering at room temperature using a crystalline CuInS 2 target and without any subsequent toxic gas, chemical or heat treatment. A systematic study of phase formation by X-ray diffraction and Raman spectroscopy and of morphology by scanning electron microscopy and atomic force microscopy was performed as function of relevant sputtering parameters: argon pressure, r.f. power and time of deposition. XRD studies show that films are amorphous until a critical thickness is reached, where they transform into crystalline chalcopyrite films with preferential (1 1 2) orientation and average grain size of 25-100 nm. At low deposition rates, smooth films were obtained, whereas at high deposition rates, films are covered with surface particles. Films were p-type conducting with bulk carrier density about 10 18 /cm 3 , determined by Hall effect measurements.
Journal of Nanostructures, 2019
In this paper, the RF power change effect on the structural, optical and electrical properties of CuO thin films prepared by RF reactive magnetron sputtering deposited on glass substrates are studied. At first, the thin films are prepared at 150, 280, 310 and 340W respectively. Then, the films are characterized by XRD, AFM, Uv-visible and four-point probe analysis respectively. The results show that the crystallite size and lattice constant of samples increased from about 20 nm to 59 nm and 4.15 to 4.51 respectively with an increase in RF power from 150 to 340W. The AFM and four-point analysis results show that the samples deposited at 150 and 340W have smooth surfaces and more surface electrical resistance than the samples deposited at 280 and 310W because the dominant phase of samples prepared at 150 and 340W are CuO2 and 280 and 310 are CuO respectively. Also, the results indicate the energy band gap increased from about 2.25 to 2.52eV with an increase in RF power from 150 to 340...
Growth and characterization of CuCdTeO thin films sputtered from CdTe–CuO composite targets
Vacuum, 2014
The incorporation of Cu and O in CdTe films grown by rf sputtering using a target comprised of a mixture of CdTe and CuO powders is studied. The Cu and O contents ranged between 5 and 20 at.% and the temperature of the substrate was 250 or 300 C. Energy dispersive spectroscopy data show the incorporation of Cu and O into the CdTe in a controlled manner. All films resulted polycrystalline with a decreased lattice parameter of the CdTe due to the incorporation of Cu and O. Large Cu and O contents promote the formation of a structural phase of the type Cu 2Àx Te. The good crystallinity of the CdTe is revealed by the LO mode and its harmonics in the Raman spectra. Bands associated to structural units of [TeO 4 ] 4À and [TeO 3 ] 2À were identified in Raman and infrared spectra. Films with large Cu and O content present an optical absorption extending from the infrared range to photon energies of the CdTe band gap.
International Journal of Engineering & Technology
Cu-based conductive oxide such as CuGaO2 is seen to be a promising transparent p-type oxide material. The study of p-type semiconductor CuGaO2 thin films have been carried out to investigate the effects of different parameters in providing the optimum result in achieving good optical transparency and conductivity of the thin film. The CuGaO2 thin films were fabricated on quartz substrate via the Radio Frequency (RF) magnetron sputtering technique with varying substrate temperatures and different annealing temperatures. The p-type thin films were deposited at a temperature ranging from room temperature, 100°C, 200°C and 300°C. The samples were also annealed varying from temperature of 500°C, 600°C, 700°C and 800°C. The fabricated sample were characterized using X-ray diffraction (XRD), UV-Visible spectroscopy, and atomic force microscope (afm). XRD showed a peak at 2θ = 36.10° (012). The optical transparency values achieved from UV-Vis spectrometer were seen to be approximately 80% a...
Preparation of delafossite CuFeO2 thin films by rf-sputtering on conventional glass substrate
Materials Letters, 2006
CuFeO 2 is a delafossite-type compound and is a well known p-type semiconductor. The growth of delafossite CuFeO 2 thin films on conventional glass substrate by radio-frequency sputtering is reported. The deposition, performed at room temperature leads to an amorphous phase with extremely low roughness and high density. The films consisted of a well crystallized delafossite CuFeO 2 after heat treatment at 450°C in inert atmosphere. The electrical conductivity of the film was 1 mS/cm. The direct optical band gap was estimated to be 2 eV.
Effect of substrate temperature on the physical properties of dc magnetron sputtered CuAlO2 films
Journal of Alloys and Compounds, 2009
Copper aluminum oxide films were prepared by direct current (dc) reactive magnetron sputtering under various substrate temperatures in the range of 303-648 K and systematically studied their physical properties. The physical properties of the films were strongly affected by the substrate temperature. The films formed at substrate temperatures <373 K were amorphous while those deposited at higher substrate temperatures (≥373 K) were polycrystalline in nature. The electrical properties of the films enhanced with substrate temperature due to the improved crystallinity. The Hall mobility of 9.4 cm 2 /V s and carrier concentration of 3.5 × 10 17 cm −3 were obtained at the substrate temperature of 573 K. The optical band gap of the films decreased from 3.87 to 3.46 eV with the increase of substrate temperature from 373 to 573 K.
Preparation and Properties of CuInS2 Thin Films Produced by the Reactive Sputtering Method
Japanese Journal of Applied Physics, 1995
A thin film of chalcopyrite CuInS 2 has been formed by sulfurization of a layered metallic precursor at 550°C in argon containing H2S. The Cu/In ratio of the film is ranged from 0,8 to 1.85. The resistivity of the film decreases by aging in air and then increases by annealing in vacuum or in air. The former effect can be attributed to gas absorption in the film which gives rise to an increase in the hole mobility, while the latter gives rise to gas desorption. The hole concentration of the films is of the order of 102o cm -3 and is almost independent of aging. Electrical conduction in the thin film is discussed in terms of hole transport crossing over an intergranular potential barrier in the polycrystalline film.