Nucleation of Cu(In, Ga)Se2 on Molybdenum Substrates

2003 ◽  
Vol 763 ◽  
Author(s):  
T. Schlenker ◽  
K. Orgassa ◽  
H. W. Schock ◽  
J. H. Werner
Keyword(s):  
Substrate Temperature ◽  
Deposition Rate ◽  
Cluster Formation ◽  
Three Dimensional ◽  
Areal Density ◽  
Growth Conditions ◽  
Exponential Dependence ◽  
Nucleation Behavior ◽  
Substrate Temperatures ◽  
Island Density

AbstractWe investigate growth mechanisms of Cu(In, Ga)Se2 on Mo films on glass, as the typical back contact for Cu(In, Ga)Se2 solar cells. A thermal evaporation process deposits Cu(In, Ga)Se2of nominal 3 nm thickness at different rates R and substrate temperatures TSub. An ultrahigh resolution scanning electron microscope serves to investigate the nucleation behavior. The deposited Cu(In, Ga)Se2 forms three-dimensional isolated nuclei, known as Volmer-Weber growth mode. Deposition rate R and substrate temperature TSub control the areal density n of the Cu(In, Ga)Se2 nuclei. We observe a power law dependence between the island density n and the deposition rate R, and an exponential dependence of the island density n on substrate temperature TSub. The theory of homogeneous nucleation explains the Cu(In, Ga)Se2 cluster formation on polycrystalline Mo and the dependence of the island density on the growth conditions.

Influence of Substrate Temperature on Deposition Rate and Optical Properties of Aluminum Oxide Thin Films Prepared by Reactive DC Sputtering Technique

2016 ◽  
Vol 675-676 ◽  
pp. 281-284
Author(s):  
Chatpawee Hom-On ◽  
Mati Horprathum ◽  
Pitak Eiamchai ◽  
Sakson Limwichean ◽  
Viyapol Patthanasetakul ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Optical Properties ◽  
Aluminum Oxide ◽  
Substrate Temperature ◽  
Deposition Rate ◽  
Oxide Films ◽  
Chemical Compositions ◽  
Transmittance Spectra ◽  
Vis Spectroscopy ◽  
Substrate Temperatures

Aluminum oxide films were grown on (100) silicon wafers and glass substrates by pulsed dc reactive magnetron sputtering deposition. In this experiment, substrate temperatures were varied from room temperature to 500°C. Grazing-incidence X-ray diffraction (GIXRD) analysis revealed that the resulting films have amorphous structures. Field-emission scanning electron microscope (FESEM) was used to characterize the morphology of the films. The films’ optical properties were determined by UV-Vis spectroscopy. The results demonstrated that the deposition rate, the surface roughness and the transmittance spectra of the aluminum oxide films were strongly influenced by the substrate temperature. The deposition rate and the surface roughness of the films were higher at higher substrate temperatures. In the range between 100°C and 200°C, the transmittance spectra were found to be lower than those of the films deposited at other substrate temperatures. This was due to the sub-aluminum oxide condition in the films. The dependence of films’ optical properties on the substrate temperature might result from the change in chemical compositions during the sputtering process.

scholarly journals High temperature ferromagnetic ordering in c-axis oriented ZnO:Mn nanoparticle thin films by tailoring substrate temperature

2014 ◽  
Vol 32 ◽  
pp. 1460341 ◽  
Author(s):  
Usman Ilyas ◽  
P. Lee ◽  
T. L. Tan ◽  
R. V. Ramanujan ◽  
Sam Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Magnetic Measurements ◽  
Deep Level ◽  
Growth Conditions ◽  
Optical Quality ◽  
Host Matrix ◽  
X Ray ◽  
Ferromagnetic Ordering ◽  
Substrate Temperatures

This study reports the enhanced ferromagnetic ordering in ZnO:Mn nanoparticle thin films, grown at different substrate temperatures using pulsed laser deposition. The optimum growth conditions were deduced from X-ray, photoemission and magnetic measurements. The X-ray measurements reveal that there was an optimum substrate temperature where the thin films showed relatively stronger texture, better crystallinity and lower strain. Substrate temperature tuned the deep level recombination centers in ZnO:Mn , which changed the optical quality by altering the electronic structure. The M-H curves, in the present study, revealed superior ferromagnetic response of 20-nm sized particles in ZnO:Mn thin film grown at a substrate temperature of 450 °C. Ferromagnetic ordering becomes weaker at higher/lower substrate temperatures due to the activation of native defects in ZnO host matrix.

Influence of Growth Parameters and Annealing on Properties of MBE Grown GaAsSbN SQWs

2005 ◽  
Vol 872 ◽  
Author(s):  
Liangjin Wu ◽  
Shanthi Iyer ◽  
Kalyan Nunna ◽  
Sudhakar Bharatan ◽  
Jia Li ◽  
...  
Keyword(s):  
Optical Properties ◽  
Substrate Temperature ◽  
Temperature Dependence ◽  
Growth Parameters ◽  
Blue Shift ◽  
Growth Conditions ◽  
Ex Situ ◽  
Single Quantum Well ◽  
Substrate Temperatures

AbstractIn this paper we report the growth of GaAsSbN/GaAs single quantum well (SQW) heterostructures by molecular beam epitaxy (MBE) and their properties. A systematic study has been carried out to determine the effect of growth conditions, such as the source shutter opening sequence and substrate temperature, on the structural and optical properties of the layers. The substrate temperatures in the range of 450-470 °C were found to be optimal. Simultaneous opening of the source shutters (SS) resulted in N incorporation almost independent of substrate temperature and Sb incorporation higher at lower substrate temperatures.The effects of ex-situ annealing in nitrogen ambient and in-situ annealing under As overpressure on the optical properties of the layers have also been investigated. A significant increase in photoluminescence (PL) intensity with reduced full width at half maxima (FWHM) in conjunction with a blue shift in the emission energy was observed on annealing the samples. In in-situ annealed samples, the PL line shapes were more symmetric and the temperature dependence of the PL peak energy indicated significant decrease in the exciton localization energy as exhibited by a less pronounced “S-shaped curve”. The “inverted S-shaped curve” observed in the temperature dependence of PL FWHM is also discussed. 1.61 μm emission with FWHM of 25 meV at 20K has been obtained in in-situ annealed GaAsSbN/GaAs SQW grown at 470 °C by SS.

FABRICATION OF GERMANIUM NANOWIRES BY OBLIQUE ANGLE DEPOSITION

2006 ◽  
Vol 05 (04n05) ◽  
pp. 523-527
Author(s):  
H. G. CHEW ◽  
W. K. CHOI ◽  
W. K. CHIM ◽  
E. A. FITZGERALD
Keyword(s):  
Raman Spectroscopy ◽  
Substrate Temperature ◽  
Deposition Rate ◽  
Rapid Thermal Annealing ◽  
Oblique Angle Deposition ◽  
Oblique Angle ◽  
Germanium Nanowires ◽  
Vapor Flux ◽  
Substrate Temperatures ◽  
Angle Deposition

In this work, the effects of flux angle, substrate temperature and deposition rate on obliquely deposited germanium ( Ge ) films have been investigated. We observed that the porosity of the film increased as the flux angle became more oblique. It was also possible to obtain polycrystalline Ge films at a substrate temperature of 200°C when deposition was performed using an oblique angle of 87° as compared to normal incident deposition. Raman spectroscopy results indicated that a higher substrate temperature during deposition led to an increase in crystallinity of the film. Agglomeration of the Ge film was reduced at a lower deposition rate and it was possible to obtain isolated polycrystalline Ge nanowires when the deposition was carried out with the vapor flux inclined at 87° to the substrate normal for substrate temperatures between 250°C to 300°C and with a deposition rate of 0.2–1.5 Å/s. Subsequent rapid thermal annealing of such nanowires resulted in the formation of facetted crystallites.

Structural Properties of Deposited ZnO Thin Films on Flexible Substrates at Various Substrate Temperatures and RF Power

2012 ◽  
Vol 576 ◽  
pp. 598-601
Author(s):  
Nur Sa’adah Muhamad Sauki ◽  
Sukreen Hana Herman ◽  
Hanafi Ani Mohd ◽  
Rusop Mahmood Mohamad
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Substrate Temperature ◽  
Deposition Rate ◽  
Rf Magnetron Sputtering ◽  
Zno Thin Films ◽  
Flexible Substrates ◽  
Rf Power ◽  
Sem Images ◽  
Substrate Temperatures

ZnO thin films were deposited on Teflon substrates by RF magnetron sputtering at different substrate temperature and different RF power. In this work, we investigated the dependence of the deposition rate and also the ZnO physical and electrical properties on the substrate temperature and RF power. It is observed that the deposition rate increased as the temperature and RF power increased. FE-SEM images confirmed that microstructure of the thin films consists of nanoparticles. XRD data confirmed that the ZnO thin films at various RF power and substrate temperature have (002) structure.

Effects of Microstructure on Photoluminescence of SrS:Eu2+,SM3+ thin Films

1993 ◽  
Vol 301 ◽  
Author(s):  
Susan Z. Hua ◽  
L. Salamanca-Riba ◽  
M. Wuttig ◽  
P. K. Soltani
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Growth Rates ◽  
Growth Conditions ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Substrate Temperatures ◽  
The Eu

ABSTRACTThe microstructure and its effects on the photoluminescence properties of SrS:Eu2+,Sm3+ thin films grown with different conditions were studied by transmission electron microscopy, x-ray diffraction and photoluminescence techniques. The SrS:Eu2+,Sm3+ thin films were prepared by e-beam evaporation at different substrate temperatures and growth rates. Both of these growth conditions affect the crystallinity of the thin films. The Sm3+ emission is stronger in the films grown at higher growth rates and at an optimum substrate temperature. We believe that the stronger Sm3+ emission is due to the higher population of Sm trivalent charge states in the films. Further increase of the substrate temperature increases the grain size in the films, but has no significant effect on the PL emission properties. In contrast, the Eu2+ emission is less sensitive to growth conditions.

Effect of Growth Conditions on Optical Response of GaAs Grown at Low Substrate Temperature by MBE

1991 ◽  
Vol 241 ◽  
Author(s):  
W. J. Schaff ◽  
S. D. Offsey ◽  
X. J. Song ◽  
L. F. Eastman ◽  
T. B. Norris ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Response Time ◽  
Substrate Temperature ◽  
Molecular Beam ◽  
Optical Response ◽  
Growth Conditions ◽  
Recent Model ◽  
Light Pulses ◽  
Substrate Temperatures

ABSTRACTThe effect of growth conditions on the properties of GaAs grown by molecular beam epitaxy at low substrate temperatures has been studied. It has been found that the response time to 100 fsec 830nm light pulses is a function of substrate temperature and arsenic flux. The reason for variation of optical response with growth conditions is related to the nature of the incorporation of excess arsenic. A recent model proposed by Warren and others is invoked to explain the change in optical response with growth conditions. Further substantiation of this model comes from experiments on the annealing of low substrate temperature GaAs which has been doped with silicon.

Change of growth orientation in Pt films epitaxially grown on MgO(001) substrates by sputtering

2002 ◽  
Vol 17 (9) ◽  
pp. 2334-2338 ◽  
Author(s):  
Kun Ho Ahn ◽  
Sunggi Baik ◽  
Sang Sub Kim
Keyword(s):  
Deposition Rate ◽  
Surface Defects ◽  
Epitaxial Film ◽  
Growth Conditions ◽  
Gradual Transition ◽  
Growth Orientation ◽  
Orientation Change ◽  
Key Driver ◽  
Pt Films ◽  
Substrate Temperatures

A drastic change of the growth orientation in epitaxial Pt films grown by sputtering on MgO(001) was observed. At higher substrate temperatures, practically pure (001) epitaxial Pt films grow. On the other hand, epitaxial (111) Pt films grow at lower substrate temperatures. Interestingly, the gradual transition from (111) to (001) orientation occurs at lower temperatures when applied at a lower deposition rate. The degree of supersaturation in growth conditions is proposed as a key driver of the orientation change. When homogeneous nucleation occurs under a higher supersaturation, a large number of nuclei grow at the flat (001) terraces possessing (111) tetrahedral orientation. Under a lower supersaturation, a small number of nuclei aligned in (001) orientation to each other form dominantly at surface defects, resulting in a (001) epitaxial film with no grains. Our results suggest that one can selectively prepare either (001) or (111) epitaxial Pt films by properly adjusting substrate temperature and/or deposition rate.

Cubic GaN Heteroepitaxy on Thin-SiC-Covered Si(001)

1999 ◽  
Vol 4 (S1) ◽  
pp. 155-160
Author(s):  
Yuichi Hiroyama ◽  
Masao Tamura
Keyword(s):  
Substrate Temperature ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Photoluminescence Intensity ◽  
Cell Temperature ◽  
Si Substrates ◽  
Gas Source ◽  
Cubic Gan ◽  
Formation Conditions ◽  
Substrate Temperatures

We have investigated the growth conditions of cubic GaN (β-GaN) layers on very thin SiC-covered Si(001) by using gas-source molecular beam epitaxy as functions of SiC layer thickness, Ga-cell temperature and substrate temperature. Under the present SiC formation conditions on Si substrates by carbonization using C2H2 gas, the SiC layers with the thickness between 2.5 and 4 nm result in the epitaxial growth of β-GaN on thus SiC-formed Si substrates. At the highest GaN growth rate of 110 nm/h ( a Ga-cell temperature of 950 °C), β-GaN layers grown at a substrate temperature of 700 °C show a nearly flat surface morphology and the fraction of included hexagonal GaN becomes negligible when compared to the results of β-GaN layers grown under other conditions of Ga-cell and substrate temperatures. Thus obtained β-GaN films have good performance in photoluminescence intensity although the FWHM of band-edge recombination peak is still wider (137 meV) than the reported values for the β-GaN on 3C-SiC and GaAs.

A Defect Density of ∼ 1014 cm-3 in Hydrogenated Amorphous Silicon Deposited at High Substrate Temperatures

1992 ◽  
Vol 258 ◽  
Author(s):  
Gautam Ganguly ◽  
Akihisa Matsuda
Keyword(s):  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Deposition Rate ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
High Substrate ◽  
Surface Mobility ◽  
Surface Hydrogen ◽  
Hydrogenated Amorphous ◽  
Substrate Temperatures

ABSTRACTThe idea of surface mobility of growth precursors determined material quality has been exploited by raising the substrate temperature above the conventional 250°C and the ensuing thermal depletion of the surface hydrogen coverage compensated by increasing the precursor flux (deposition rate) to prepare ultra low defect density hydrogenated amorphous silicon.

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