Nucleation and Growth Behavior of Quaternary-Sputtered Copper Indium Gallium Diselenide Thin Films

2012 ◽  
Vol 1447 ◽  
Author(s):  
Jason D. Myers ◽  
Jesse A. Frantz ◽  
Robel Y. Bekele ◽  
Vinh Q. Nguyen ◽  
Allan Bruce ◽  
...  

AbstractIn the past two decades, the growing global demand for solar energy has spurred scientific interest in alternative technologies to conventional silicon. In particular, CuIn1-xGaxSe2 (CIGS) has emerged as a competitor. We have developed a scalable deposition technique using RF magnetron sputtering of quaternary CIGS. Notably, the resulting films do not require postselenization, reducing processing time and cost. We have fabricated devices above 10% efficiency using this approach, showing its promise as a production method for highperformance CIGS photovoltaics. However, the morphology of the sputtered CIGS layer is markedly different from conventional evaporated films; grain sizes vary through the thickness of the film, with numerous small grains dominating at the Mo/CIGS interface that then either terminate or grow in an inverted-pyramid fashion to form large, columnar grains at the CIGS/CdS interface.To better understand the origin of this morphology, we have studied the growth behavior of the CIGS layer using a combination of atomic force microscopy and electron microscopy to observe initial nucleation and grain growth behavior of quaternary-sputtered CIGS. We also discuss the effects of interfacial layers at the Mo/CIGS interface, demonstrating a novel wetting layer that conformally coats the Mo surface.

2011 ◽  
Vol 493-494 ◽  
pp. 473-476
Author(s):  
E.O. Lopez ◽  
F.F. Borghi ◽  
Alexandre Mello ◽  
J. Gomes ◽  
Antonella M. Rossi

In this present work, we characterize HAp thin films deposited by dual magnetron sputtering device DMS on silicon (Si/HAp). The sputtering RF power was varied from 90 watts to 120 watts and deposition times from 60 to 180 minutes. The argon and oxygen pressure were fixed at 5.0 mTorr and 1.0 mTorr, respectively. Grazing incidence X-ray diffraction (GIXRD) from synchrotron radiation, infrared spectroscopy (FTIR) and atomic force microscopy (AFM) were used for the structural characterization. At lower deposition times, a crystalline phase with preferential orientation along apatite (002) and a disordered nanocrystalline phase were identified. The coating crystallinity was improved with the increase of the deposition time besides the sputtering power.


2011 ◽  
Vol 466 ◽  
pp. 65-72 ◽  
Author(s):  
Ozgur Ekincioglu ◽  
M. Hulusi Ozkul ◽  
Yoshihiko Ohama ◽  
Silvia Patachia ◽  
Georgeta Moise

Macro-defect-free (MDF) cements are cement-polymer composites and were developed by Birchall et al. three decades ago. The composites are produced by mixing small amounts of polymer and water with cement. However, they have a different production method than that of cement pastes, which was inspired by rubber production. Mixtures of cement, polymer and water are processed by using a two-roll mill. The composites are known with their high flexural strengths. Unfortunately, there are not any known commercial products using MDF cements because of their poor durability under moisture. In this study, MDF cements were prepared by using poly(vinyl alcohol--vinyl acetate) PVA, calcium aluminate cements and two different types of epoxy resins. Epoxy resins were a diglycidyl ether of bisphenol A and a mixture of a diglycidyl ethers of bisphenol A and F. Durability performance was compared with respect to biaxial flexural strengths, contact angle and atomic force microscopy (AFM) for the specimens stored in water.


2015 ◽  
Vol 1117 ◽  
pp. 139-142 ◽  
Author(s):  
Marius Dobromir ◽  
Radu Paul Apetrei ◽  
A.V. Rogachev ◽  
Dmitry L. Kovalenko ◽  
Dumitru Luca

Amorphous Nb-doped TiO2 thin films were deposited on (100) Si and glass substrates at room temperature by RF magnetron sputtering and a mosaic-type Nb2O5-TiO2 sputtering target. To adjust the amount of the niobium dopant in the film samples, appropriate numbers of Nb2O5 pellets were placed on the circular area of the magnetron target with intensive sputtering. By adjusting the discharge conditions and the number of niobium oxide pellets, films with dopant content varying between 0 and 16.2 at.% were prepared, as demonstrated by X-ray photoelectron spectroscopy data. The X-ray diffraction patterns of the as-deposited samples showed the lack of crystalline ordering in the samples. Surfaces roughness and energy band gap values increase with dopant concentration, as showed by atomic force microscopy and UV-Vis spectroscopy measurements.


2012 ◽  
Vol 545 ◽  
pp. 290-293
Author(s):  
Maryam Amirhoseiny ◽  
Hassan Zainuriah ◽  
Ng Shashiong ◽  
Mohd Anas Ahmad

We have studied the effects of deposition conditions on the crystal structure of InN films deposited on Si substrate. InN thin films have been deposited on Si(100) substrates by reactive radio frequency (RF) magnetron sputtering method with pure In target at room temperature. The nitrogen gas pressure, applied RF power and the distance between target and substrate were 2×10-2 Torr, 60 W and 8 cm, respectively. The effects of the Ar–N2 sputtering gas mixture on the structural properties of the films were investigated by using scanning electron microscope, energy-dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction techniques.


2003 ◽  
Vol 800 ◽  
Author(s):  
Y. D. Lanzerotti ◽  
J. Sharma ◽  
R. W. Armstrong ◽  
R. L. McKenney ◽  
T. R. Krawietz

ABSTRACTThe characteristics of TNT (trinitrotoluene) crystals in the fracture surface of Composition B (a melt-cast mixture of TNT and RDX) have been studied using atomic force microscopy (AFM). The size of TNT crystals has been examined by analyzing the surface structure that is exhibited after mechanical failure of the Composition B. The failure occurs when the material is subjected to high acceleration in an ultracentrifuge and the shear or tensile strength is exceeded. AFM examination of the topography of the Composition B fracture surface reveals fracture across columnar grains of the TNT. The width of the columnar TNT grains ranges in size from ∼ 1 μm to ∼ 2 μm. Their height ranges in size from ∼ 50 nm to ∼ 300 nm. Flat TNT columns alternate with TNT columns containing river patterns that identify the direction of crack growth. Steps in the river patterns are a few nanometers in depth. The TNT constitutent fracture surface morphology is shown to occur on such fine scale, beginning from adjacent columnar crystals only 1–2 μm in width, and including river marking step heights of only a few nanometers, that AFM-type resolution is required.


2011 ◽  
Vol 1354 ◽  
Author(s):  
N Srinivasa Rao ◽  
A P Pathak ◽  
G Devaraju ◽  
V Saikiran ◽  
S V S Nageswara Rao

ABSTRACTGe nanocrystals embedded in silica matrix have been synthesized on Si substrate by co-sputtering of SiO2 and Ge using RF magnetron sputtering technique. The as-deposited films were subjected to microwave annealing at 800 and 9000C. Rutherford backscattering spectrometry (RBS) has been used to measure the Ge composition and film thickness. The structural characterization was performed by using X-ray diffraction (XRD) and Raman spectrometry. XRD measurements confirmed the formation of Ge nanocrystals. Raman scattering spectra showed a peak of Ge-Ge vibrational mode around 299 cm−1, which was caused by quantum confinement of phonons in the Ge nanocrystals. Surface morphology of the samples was studied by atomic force microscopy (AFM). Variation of nanocrystal size with annealing temperature has been discussed. Advantages of microwave annealing are explained in detail.


Tribology ◽  
2006 ◽  
Author(s):  
A. H. Jayatissa ◽  
D. Wagner ◽  
S. Sorin ◽  
N. X. Randall

The mechanical properties of CrN films coated by radio frequency (rf) magnetron sputtering method were investigated. CrN films were coated on stainless steel, silicon wafer and glass substrates using sputtering of a Cr target in nitrogen ambient. The films were coated by varying the deposition temperature, nitrogen partial pressure and rf power density. The films coated were characterized by nanoindentation method, microhardness, optical, and corrosion tests. In order to use CrN as mechanical coating material, the surface roughness, hardness and adhesion properties have to be determined. The film properties were measured using atomic force microscopy and nanoindentation method and analyzed as a function of deposition conditions. It was found that these properties can be varied by changing the deposition conditions.


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