Fabrication and Characterization of Al/p-CuInAlSe2 Thin Film Schottky Diodes

Al/p-CuInAlSe2 polycrystalline schottky diodes fabricated by flash evaporation method were undertaken for their electrical analysis at room temperature. Diode parameters of the undertaken diodes were then derived from the current-voltage (I-V) as well as capacitance-voltage (C-V) characteristics. It has been observed that the schottky barrier height deduced from the room temperature I-V is lower to that obtained from the C-V characteristics and is attributed to the fact that I-V analysis includes both the image force and dipole lowering effects and is also reduced by the tunneling and leakage currents. The slope variation of the frequency dependent C – 2-V characteristics for the Al/p-CuInAlSe2 Schottky diode at varying frequency values from 50 kHz to 1 MHz suggests a large density of slow traps or interface states at the M-S junction. As emerging from the parameters values energy band diagram of Al and P-CuInAlSe2 has been reconstructed. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3100

Mechanochemically Synthesized CIGS Nanocrystalline Powder for Solar Cell Application

Copper Indium Gallium Diselenide (CIGS) is a compound semiconductor material from the group of I-III-VI. The material is a solid solution of copper, indium and selenium (CIS) and copper, gallium and selenium with an empirical formula of CuIn(1 – x)GaxSe2, where 0 x 1. CIGS has an exceptionally high absorption coefficient of more than 105 cm – 1 for 1.5 eV. Solar cells prepared from absorber layers of CIGS materials have shown an efficiency higher than 20 %. CuIn(1 – x)GaxSe2 (x 0.3) nanocrystalline compound was mechanochemically synthesized by high-energy milling in a planetary ball mill. The phase identification and crystallite size of milled powders at different time intervals were carried out by X-ray diffraction (XRD). The XRD analysis indicates chalcopyrite structure and the crystallite size of about 10 nm of high-energy milled CIGS powder after two and half hours of milling. An attempt for preparing the thin film from CIGS nanocrystalline powder was carried out using the flash evaporation technique. Scanning electron microscopy (SEM) reveals uniform distribution of CIGS particles in thin film. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3100

Structural Microstructural and Electrical Transport Studies of Ba(Fe0.25Eu0.25Nb0.5)O3

The complex multifunctional ceramic Ba(Fe0.25Eu0.25Nb0.5)O3 (BFEN) has been synthesized. The structural studies show two iso-structured phases related with BFN and BEN co-exists in the compound. The high dielectric constant and low dielectric loss of the compound below 575 K promises industrial applications. The activation energies obtained from the Arrhenius analysis of dc conductivity supports possible ferroelectric transition at elevated temperatures. Thus the desirable properties of two different compounds viz. multiferroic properties of BFN and high quality factor of BEN are successfully incorporated in a single compound. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3101

Barrier inhomogeneities of Al/p-In2Te3 thin film Schottky diodes

The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of p-In2Te3/Al thin films Schottky diodes papered by Flash Evaporation technique were measured in the temperature range 303-335 K have been interpreted on the basis of the assumption of a Gaussian distribution of barrier heights (φbo) due to barrier height inhomogeneities that prevail at the interface. It has been found that the occurrence of Gaussian distribution of BHs is responsible for the decrease of the apparent BH (φbo) and increase of the ideality factor (η). The inhomogeneities are considered to have a Gaussian distribution with a mean barrier height of (φbm) and standard deviation (σs) at zero-bias. Furthermore, the activation energy value (φb) at T = 0 and Richardson constant (A**) value was obtained as 0.587 eV and 3.09 Acm– 2 K– 1 by means of usual Richardson plots. Hence, it has been concluded that the temperature dependence of the I-V characteristics of p-In2Te3/Al Schottky Diodes can be successfully explained on the basis of TE mechanism with a Gaussian distribution of the BHs. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2790

Simulation of CIGS thin film solar cells using AMPS-1D

The solar cell structure based on copper indium gallium diselenide (CIGS) as the absorber layer, cadmium sulfide (CdS) as a buffer layer un-doped (i) and Aluminium (Al) doped zinc oxide (ZnO) as a window layer was simulated using the one dimensional simulation program called analysis of microelectronic and photonic structures (AMPS-1D). In the simulation, the thickness of CIGS layer was varied from 300 to 3000 nm. The rest of layer’s thicknesses were kept constant, viz. 60 nm for CdS, and 80 nm and 500 nm for i- and Al-ZnO, respectively. By varying thickness of CIGS layer the simulated device performance was demonstrate in the form of current-voltage (I-V) characteristics and quantum efficiency (QE). When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2209

Laser Induced Damage Studies on Al2O3, SiO2, and MgF2 Thin Films for Anti-Reflection Coating Application in High Power Laser Diode

The laser diode facet damage is one of the impeding factors of the high-power laser diode operation. To overcome this restriction laser diode facet coating can be utilized. During the high power operation of the laser diode, it is observed that the single layer anti reflection (AR) coating at the front facet shows optical damage while the multilayer high reflective coating at the back facet remains undamaged. To determine the “damage threshold” of the materials used for AR coating, an e-beam evaporated Al2O3, MgF2, and SiO2 single layer thin films on GaAs substrate have been optimized for the wavelength ~ 1060 nm. The diode pumped Q-switched Neodymium Yttrium Aluminum Garnet (Nd:YAG) laser (1064 nm) was used to da-mage the samples. The damage on the sample was observed under the microscope. The effective damage radius on the samples was 150 m and average continuous wave laser induced damage threshold was found 10 W. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3101

Magnetron sputtered Al-ZnO Thin films for photovoltaic applications

The optimization process of the RF magnetron sputtered Al - doped ZnO (AZO) thin films was carried out by studying its structural, optical, electrical, and morphological properties at different RF power and different working pressures for its use as a front-contact for the copper indium diselenide (CIS) based thin film solar cell. The structural study suggests that the preferred orientation of grains along the ( 002) plane having a hexagonal structure of the grains. The optical and electrical properties suggest that the films show an average transmission of 85 % and a resistivity of the order of 10-4 Wcm. The morphology analysis suggests the formation of packed grains having a homogeneous surface. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2210

The optimization of optical thin films deposition using in-situ reflectivity measurements and simulation

We have optimized and automated the experimental in-situ reflectivity measurement system for the laser diode (LD) facet coating. We have also developed a reflectivitysimulator program that gives the reflectivity data as a function of the thickness of the film (single or multi-layer) for a given wavelength, which aids in optimizing the above parameters while monitoring the coating of the films in-situ. We report the results for the in-situ reflectivity of a single layer MgF2 and a quarter-wave optical thick three bi-layer pairs of MgF2 and silicon on GaAs as a substrate for both the cases. We have achieved up to 83 % experimental reflectivity for the latter case. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2207

Molybdenum back-contact optimization for CIGS thin film solar cell

Molybdenum (Mo) thin films are most widely used as an ohmic back-contact in the copper indium diselenide (CIS) and its alloy copper indium gallium diselenide (CIGS) based thin film solar cell. Radio frequency (RF) magnetron sputtering system used to deposit Mo thin films on soda lime glass substrate. The deposition was carried out using argon (Ar) gas at different Ar controlled (working) pressures (1 mTorr to 10 mTorr) and at different RF powers (60 W to 100 W). The influence of both the working pressure and the RF power on the Mo thin films was studied by investigating its structural, morphological, electrical, and optical measurements. The results reveal that a stress-free, low-sheet-resistance (~1 W/), and reflecting (~ 55 %) Mo thin film was observed at 1 mTorr working pressure and 100 W RF power. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2211

Investigation of Urbach Energy of CdS Thin Films as Buffer Layer for CIGS Thin Film Solar Cell

CdS (Cadmium Sulphide) has been studied as a buffer layer to form heterojunctions layer with an absorber layer in photovoltaic applications. Different techniques have accounted for deposition CdS layer. We had studied CdS thin film layer by thermal evaporation and chemical bath deposition (CBD) techniques. Structural, optical, electrical and Photoluminescense (Pl) analysis of CdS thin films have been studied. Urbach energy, dark resistivity and light resistivity also have been estimated