Synthesis and Characterization of α-Fe2O3 Nanoparticles Prepared by PLD at Different Laser Energies

In this paper, ferric oxide nanoparticles) Fe2O3 NPs( were synthesized directly on a quartz substrate in vacuum by pulse laser deposition technique using Nd:YAG laser at different energies (171, 201,363 mJ/pulse). The slides were then heated to 700o C for 1 hour. The structural, optical, morphological, and electrical properties were studied. The optical properties indicated that the prepared thin films have an energy gap ranging from 2.28 to 2.04 eV. The XRD results showed no lattice impurities for other iron oxide phases, confirming that all particles were transformed into the α-Fe2O3 phase during the heating process. The AFM results indicated the dependence of nanoparticles size on the laser energy. As the laser energy increased, the average grain size increased from 72.6 nm to 79.02 nm. Hall effect measurement indicated that the film was an n-type semiconductor.

STRUCTURAL AND ELECTRICAL PROPERTIES OF (CDO)1-X (V2O5)X PREPARED BY PULSE LASER DEPOSITION TECHNIQUE FOR SOLAR CELL APPLICATIONS

In this work ,pure and doped(CdO)thin films with different concentration of V2O5x (0.0, 0.05, 0.1 ) wt.% have been prepared on glass substrate at room temperature using Pulse Laser Deposition technique(PLD).The focused Nd:YAG laser beam at 800 mJ with a frequency second radiation at 1064 nm (pulse width 9 ns) repetition frequency (6 Hz), for 500 laser pulses incident on the target surface At first ,The pellets of (CdO)1-x(V2O5)x at different V2O5 contents were sintered to a temperature of 773K for one hours.Then films of (CdO)1-x(V2O5)x have been prepared.The structure of the thin films was examined by using (XRD) analysis..Hall effect has been measured in orded to know the type of conductivity, Finally the solar cell and the efficiency of the CdO:V2O5 cells have been studied.

Influence of Laser Energy on the Optical Properties of Ag2S ITO Thin Films Prepared by the PLD Technique

Nanocrystalline silver sulfide (Ag2S) thin films were prepared by the pulse laser deposition technique (PLD) on the indium-tin oxide (ITO) substrate at room temperature. In the PLD technique, an Nd : YAG laser with a wavelength of 1064 nm at different laser energies from 400 to 900 mJ is used with an increment of 100 mJ in each step with 200 pulses for each sample. The optical properties such as the refraction index n, absorption coefficient a, and extinction coefficient k are examined using the transmission and absorbance measurements on a UV-Vis-NIR spectrophotometer in the wavelength range (200–1100) nm. The average extinction coefficient is found between 0.076–0.163, while the average refractive index is between 2.214–2.528. The energy band gap decreases from 2.39 to 1.9 eV with increasing the laser energy.

Optical Investigations of Nanophotonic LiNbO3 Films Deposited by Pulsed Laser Deposition Method

The nanocrystalline structure of Lithium niobate (LiNbO3) was prepared and deposited onto substrate made of quartz by utilize pulse laser deposition technique. The effect of substrate temperature on the structural, optical and morphological properties of lithium niobate photonic film grown was studied. The chemical mixture was prepared by mixing the raw material (Li2CO3, Nb2O5) with Ethanol liquid without any further purification, at time of stirrer 3hrs but without heating, then annealing process the formed material at 1000C° for 4hrs. We characterized and analyzed the LiNbO3 nanostructure thin films by utilize Ultra-Violet Visible (UV-vis). The UV-vis measurements show that, when the substrate temperature increases, the values of transmission, absorption and energy band gap will decreased, but the values of reflection and refractive index will increased. That means the LiNbO3 thin film prepared at substrate temperatures 300C° give the best result for manufacture the optical waveguide.

Morphological and optical properties of V2O5:TiO2 thin film prepared by PLD technique

In this work, pure and doped Vanadium Pentoxide (V2O5) thin films with different concentration of TiO2 (0, 0.1, 0.3, 0.5) wt were obtained using Pulse laser deposition technique on amorphous glass substrate with thickness of (250)nm. The morphological, UV-Visible and Fourier Transform Infrared Spectroscopy (FT-IR) were studied. TiO2 doping into V2O5 matrix revealed an interesting morphological change from an array of high density pure V2O5 nanorods (~140 nm) to granular structure in TiO2-doped V2O5 thin film .Transform Infrared Spectroscopy (FTIR) are used to analyze structural properties of as-deposit. The transmittance and absorption of each film, in the spectral range 300 to 1100 nm, were measured from which the optical constants (Refractive index, Absorption coefficient, Extinction coefficient and Energy gap) were determined .The energy band gap of the films was found to be change from (2.38 to 2.9) eV when the concentration of TiO2 increases from (2.78 to 2.9 ) eV The results showed a significant improvement in the transmittance and refractive index in TiO2 doped V2O5 thin films .All measured values were in consistent with other previous studies.

ZnO Characterization of ZnO/GaAs heterojunction

ZnO thin films have been prepared by pulse laser deposition technique at room temperatures (RT). These films were deposited on GaAs substrate to form the ZnO/GaAs heterojunction solar cell. The effect of annealing temperatures at ( RT,100, 200)K on structural and optical properties of ZnO thin films has been investigated. The X-ray diffraction analysis indicated that all films have hexagonal polycrystalline structure. AFM shows that the grains uniformly distributed with homogeneous structure. The optical absorption spectra showed that all films have direct energy gap. The band gap energy of these films decreased with increasing annealing temperatures. From the electrical properties, the carriers have n-type conductivity. From C-V measurement of ZnO/GaAs heterojunciton solar cell at frequency 100, 200 KHz, It is found that built–in potential (Vbi) increases with increase frequency. Also, from I-V characteristic it is observed that the ideality factor is 2.7. Short-circuit current (Isc) is 4.0mA/cm2, open circuit voltage (Voc) is 0.5V, fill factor ( F.F) is 0.7 and the efficiency is about 6.0 %.

Current-voltage curves of eutectic In-Sb-Te thin films for phase change memory devices

Purpose The purpose of this paper is to investigate electrical properties of eutectic In8Sb8Te84 and In10Sb51Te39 as made thin films to evaluate their potential for non-volatile phase-change memories, once the thermal measurements are very optimistic. Design/methodology/approach The films were deposited by pulse laser deposition technique. By using a very simple home-made cell, transversal current-voltage curves films were measured involving both voltage controlled-pulses generator and current controlled-pulses generator, employing different pulse shapes: triangular and sine shaped. Findings The memory effect, characteristic of a typical phase-change memory material, was observed in both materials under research. For higher tellurium content in the film, lower is the value of threshold voltage. Research limitations/implications Further studies on endurance, scaling and SET/RESET operations are needed. Practical implications The values of the key parameters, threshold voltage and hold voltage are comparable with those of Ge2Sb2Te5, GeTe and Sb2Te being considered to date as the main compounds for PCM devices. Originality/value The conduction mechanism in the amorphous regime is agreed with Poole–Frenkel effect in deep traps.