Layer Growth Mode Research Articles

Effects of the growth parameters on the surface quality of InN films

On the basis of the improved Stillinger–Weber potential model, the growth process of an indium nitride (InN) film on a gallium nitride (GaN) substrate has been simulated by molecular dynamics. The effects of growth conditions, including the incident energy, polarity of the surface of the GaN substrate, substrate temperature, and deposited N:In atomic ratio, on the surface quality of the InN film have been investigated. We find that atoms with high incident energy have high mobility, which significantly improves the structures of the protrusions and pits on the surface of the film, thereby enhancing the surface quality. However, too high incident energy enhances the sputtering effect of the deposited particles on the surface atoms of the substrate and the destruction of the film, thereby reducing the density. On the basis of the optimal incident energy, the difference in the growth mode of InN films on the Ga-termination polarity surface and N-termination polarity surface is analyzed. At low temperatures, a three-dimensional island growth mode is present on the N-termination polarity surface and a two-dimensional layer growth mode is present on the Ga-termination polarity surface. It is easier to produce InN films with excellent surface quality on the Ga-termination polarity at low temperatures. Furthermore, according to the results obtained under different substrate temperatures and atomic deposition ratios, in an In-enriched environment, excessive In atoms are prone to form agglomerated island structures on the film surface, and the low-temperature substrate is more prone to produce an InN film with high surface quality. In an N-enriched environment, excessive N atoms combine with In atoms on the film surface to form a stepped island structure, and they are more prone to grow into an InN film with high surface quality on a high-temperature substrate.

On the Microcrystal Structure of Sputtered Cu Films Deposited on Si(100) Surfaces: Experiment and Integrated Multiscale Simulation.

Sputtered Cu/Si thin films were experimentally prepared at different sputtering pressures and characterized using X-ray diffraction (XRD) and an atomic force microscope (AFM). Simultaneously, an application-oriented simulation approach for magnetron sputtering deposition was proposed in this work. In this integrated multiscale simulation, the sputtered atom transport was modeled using the Monte Carlo (MC) and molecular dynamics (MD) coupling method, and the deposition of sputtered atoms was simulated using the MD method. This application-oriented simulation approach was used to simulate the growth of Cu/Si(100) thin films at different sputtering pressures. The experimental results unveiled that, as the sputtering pressure decreased from 2 to 0.15 Pa, the surface roughness of Cu thin films gradually decreased; (111)-oriented grains were dominant in Cu thin films and the crystal quality of the Cu thin film was gradually improved. The simulation results were consistent with the experimental characterization results. The simulation results revealed that the transformation of the film growth mode from the Volmer-Weber growth mode to the two-dimensional layered growth mode resulted in a decrease in the surface roughness of Cu thin films; the increase in the amorphous compound CuSix and the hcp copper silicide with the decrease in the sputtering pressure was responsible for the improvement of the crystal quality of the Cu thin film. This work proposed a more realistic, integrated simulation scheme for magnetron sputtering deposition, providing theoretical guidance for the efficient preparation of high-quality sputtered films.

Physical Properties of an Ultrathin Al2O3/HfO2 Composite Film by Atomic Layer Deposition and the Application in Thin-Film Transistors

A high-quality ultrathin dielectric film is important in the field of microelectronics. We designed a composite structure composed of Al2O3/HfO2 with different Al2O3/HfO2 cycles prepared by atomic layer deposition (ALD) to obtain high-quality ultrathin (1-12 nm) dielectric films. Al2O3 protected HfO2 from interacting with the Si substrate and inhibited the crystallization of the HfO2 film. High permittivity material of HfO2 was adopted to guarantee the good insulating property of the composite film. We investigated the physical properties as well as the growth mode of the composite film and found that the film exhibited a layer growth mode. The water contact angle and grazing-incidence small-angle X-ray scattering analyses revealed that the film was formed physically at 3 nm, while the thickness of the electrically stable film was 10 nm from grazing-incidence wide-angle X-ray scattering and dielectric constant analyses. The composite film was applied as a dielectric layer in thin-film transistors (TFTs). The threshold voltage was decreased to 0.27 V compared to the organic field-effect transistor with the single HfO2 dielectric, and the subthreshold swing was as small as 0.05 V/dec with a carrier mobility of 49.2 cm2/V s. The off-current was as low as 10-11 A, and the on/off ratio was as high as 5.5 × 106. This ALD-prepared composite strategy provides a simple and practical way to obtain the high-quality dielectric film, which shows the potential application in the field of microelectronics.

Optimization of Pulsed Laser Deposition Parameters for Single-Crystalline (011) Oriented Tetragonal Pzt Thin Films

Recent advances in nanotechnology applications require the processing of high-quality thin films. A systematic study of the optimization of Pulsed deposition parameters for (110) oriented tetragonal PZT thin films is reported in this work. Prior to film deposition, a highly tetragonal Pb(Zr0.5, Ti0.95) or PZT 05/95 was selected to be deposited on (110) oriented Strontium titanate, SrTiO3 substrate, STO(110) to insure small compressive misfit strain. Unlike SRO, the LSOM bottom electrode was then successfully grown at 620 °C, 1.0 J/cm2 and a target-substrate distance of 3.9 cm. Finally, deposition parameters of PZT were progressively optimized through monitoring film morphological changes. Monocrystalline PZT films of different thicknesses with layer–by–layer growth mode were finally realized at a deposition temperature of 550 °C, laser energy of 1.0 J/cm2, background pressure of 200 mTorr O2, while deposition rate was 3 Hz and target-substrate distance of 3.1 cm. The optimal film growth rate was finally estimated to be 0.3 nm/100 Pulses.

MOCVD growth of ZrN thin films on GaN/Si templates and the effect of substrate temperature on growth mode, stress state, and electrical properties

Zirconium nitride (ZrN) is a candidate for contact metal and diffusion barrier in ohmic contacts for GaN-based devices due to its superior electrical conductivity and corrosion resistance. This paper reported ZrN films deposited on GaN/Si templates using metal-organic chemical vapor deposition (MOCVD) and analyzed the effect of substrate temperature (T s) on its growth mode, film stress, as well as electrical properties. Firstly, the surface morphology and film roughness of the resultant ZrN epilayers were investigated, which were found to vary dramatically with T s. Then, a temperature-dominated crystal formation process was reasonably proposed, revealing the transfer from the island to layer growth mode and the augmentation of the growth rate of ZrN with elevated T s. Stress information was obtained from the position of XRD diffraction peaks, indicating large in-plane lattice stretching in ZrN film and the presence of compressive stress in the GaN/Si template. The stress states can be related to island merger and thermal mismatch between ZrN and GaN, which proved satisfyingly advantageous in preventing the GaN layer from cracking during the subsequent preparation procedure. In addition, XPS surface and interface investigations were performed to identify the chemical state and the atomic content of the ZrN film, which also implied a relatively clear interface between the ZrN epilayer and GaN/Si template. Furthermore, Hall tests proved the resistivity of ZrN thin film can reach a minimum of 2.28 × 10−4 Ω cm, owing to the grain boundary chaining and flat film surface at high temperatures. Overall, it appears to have promising prospects for its application in the contact layer and diffusion barrier of ohmic contact in GaN-based devices.

Parametric Identification of Nucleation Modes By Model Method for Alkaline Zn and Znfe Electrolytes Application to Pulsed Currents

Long-term protection of metallic parts from atmospheric exposure is frequently made by electrodeposited zinc alloys obtained from alkaline electrolytes because of their ease of use and fulfilling properties. The present study deals with the optimization of ZnFe sacrificial coating on steel and aluminum substrate in the frame of the ATLAS project -Alternative TechnoLogies for improved Anticorrosion Solutions- managed by the IRT M2P. It has been noted that coatings properties are linked to the electrolyte composition and the use of pulsed current acting as a reiteration of germination steps. In this frame, the modelling of a nucleation process followed by diffusion limited three-dimensional growth is an area of promising interest. The study of current transient responses to a potential step (chronoamperometry) is a relevant methodology [1]. This allows the determination of several parameters such as nucleation rate, nucleation density, and number of active sites. Different competing models are available, such as Scharifker and Hills [2], Scharifker and Mostany [3] or Bewick [4]. By using the model method i.e. the identification of the model parameters by error minimization, it is possible to reach an accurate description of the first layer growth and nucleation mode (instantaneous or progressive).[1] D. Vasilakopoulos, M. Bouroushian, et N. Spyrellis, Electrochimica Acta, 54(9), p. 2509-2514, 2009[2] Scharifker, B. & Hills, G. Theoretical and experimental studies of multiple nucleation. Electrochimica Acta 28, 879–889 (1983)[3] Scharifker, B. R. & Mostany, J. Three-dimensional nucleation with diffusion controlled growth. J. Electroanal. Chem. Interfacial Electrochem. 177, 13–23 (1984).[4] I. Danaee, « 2D–3D nucleation and growth of palladium on graphite electrode », Journal of Industrial and Engineering Chemistry, 19(3), p. 1008-1013, (2013)

Formation mechanism and photoelectric properties of Al2O3 film based on atomic layer deposition

The formation mechanism of metal oxide films is very important to nanomanufacturing and microelectronic devices. We have prepared the aluminum oxide (Al2O3) films with the thicknesses ranging from 1 to 30 nm by using atomic layer deposition technology. By investigating their morphologies and optoelectrical properties, we found that the Al2O3 films grow on substrate via a layer growth mode by atomic force microscope measurement. Grazing incidence small-angle x-ray scattering further proved that a layer structure parallel to the substrate at the thickness of 5 nm. The water contact angle revealed that 5 nm is critical thickness of physical-film formation. The analysis of dielectric characteristics and the performance of thin film transistors revealed that 30 nm is critical thickness of dielectric-film formation. The understanding on structure–function relationships is necessary to realize the potential application of metal oxide films.

Study of Pt growth on Si, Al2O3, Au, and Ni surfaces by plasma enhanced atomic layer deposition

Atomic layer deposition is a powerful technique for achieving atomic-level control in the deposition of thin films and nanoparticles. The ultrathin noble metal films can be applied in many functional devices, but it is a challenge to obtain such films since the island growth mode generally happens instead of the layer growth mode. In this work, the nucleation and growth of platinum on Si, Al2O3, Au, and Ni substrates were studied using (MeCp)PtMe3 and O2 plasma as a precursor and a co-reactant, respectively. The evolution of Pt coverage on different surfaces was observed and discussed based on the experimental results by x-ray photoelectron spectra. The chemical adsorption of the precursor and the following processes like metal atom diffusion on substrate surfaces and up-stepping onto the existing metal islands were considered to dominate the growth before continuous films formed. The chemisorption determined the metal coverage on bare substrate surfaces, and the total coverage was influenced by metal atom diffusion and up-stepping behaviors that are determined by surface energy relationships between the deposited metal and substrate surfaces. Pt films were easier to form on Al2O3 and Ni surfaces compared with on Si and Au surfaces, respectively. A model was proposed to help to understand the mechanisms in the nucleation and growth processes, involving the chemisorption, diffusion, and up-stepping, which contributed to prepare ultrathin continuous Pt films on different substrates.

Step-controlled growth of MAPbBr3 single crystal and temperature-dependent variations of MA+ cations during nonphase transition

MAPbBr3 perovskite crystals have attracted significant attention due to their outstanding performance in various optoelectronic applications. However, further understanding for the growth mechanism of MAPbBr3 and its temperature-dependent variations of MA+ should be addressed. In this study, MAPbBr3 single crystal was grown using the inverse temperature crystallization method with a crystallization temperature of approximately 60 °C. Optical microscopy and atomic force microscopy were used to illustrate the surface structure of the resultant MAPbBr3. The results show that there is a layered growth mode with concave grooves and 2D nuclei on its surface. In situ variable-temperature Raman measurements were performed on the MAPbBr3 crystal at a temperature range of 80–300 K. The narrowing of Raman bands unrelated to the phase transition of the crystal was observed around 100 K. By combining the variable-temperature X-ray diffractometry results from 80 to 105 K, the reason can be attributed to the lattice distortion and vibration within the crystals.

Inner Encapsulating Approach for Moisture‐Stable Perovskite Solar Cells

The degradation of the perovskite layer in atmospheric air is a critical bottleneck for the commercialization of perovskite solar cells (PSCs). As the moisture and oxygen in air penetrate the charge transport layer/top metal electrode interface, both adjacent layers and perovskite layers decompose in the PSCs. Herein, moisture‐stable inverted PSCs (I‐PSCs) based on methylammonium lead triiodide (MAPbI3) by introducing amine‐functionalized small molecules as metal adhesive layers (MALs) between the electron transport layer (ETL) and metal electrode (here, Cu) are demonstrated. A strong coordination bond of CuN forms at the Cu/MAL interface, leading to the layer–layer growth mode for the dense formation of Cu electrodes with a strong adhesion to the ETL. Thus, this modified electrode prevents the ingress of moisture into the I‐PSCs, resulting in outstanding moisture stability; the efficiency of I‐PSCs retains 90% of the initial efficiency after 200 days of exposure to atmospheric air (25 °C, relative humidity [RH] ≈20–40%). Under harsher conditions (e.g., 25 °C/RH65%, 25 °C/RH85% and immersion in water) for a considerable time period, the modified I‐PSCs manifest relatively no degradation compared with the pristine I‐PSCs. It is believed that this breakthrough provides a significant impact on improving the stability of I‐PSCs.

Controlled ultra-thin oxidation of graphite promoted by cobalt oxides: Influence of the initial 2D CoO wetting layer

The interaction of CoO with highly oriented pyrolytic graphite (HOPG) was studied using a set of complementary techniques. The morphology of the CoO thin film was determined using atomic force microscopy (AFM), whereas the electronic structure was investigated using X-ray absorption (XAS) and photoemission (PES) spectroscopies. The experimental spectra were analyzed using a configuration interaction CoO6 cluster model calculation. The early stages of growth are characterized by the formation of a CoO wetting layer at the CoO/HOPG interface. The electronic structure of the CoO wetting layer presents a clear 2D character, which is closer to the 2D HOPG substrate than to the 3D CoO bulk. This character of the wetting layer explains the posterior formation of CoO islands and excludes the alternative layer by layer growth mode. Further, the interaction between the CoO wetting layer and the outermost graphite layer favors the oxidation of the HOPG substrate which can be controlled by the thickness of the deposited CoO overlayer.

Detailed Structural and Morphological Characterization of InGaN Thin Films Grown by RF Magnetron Sputtering with Various Substrate Temperature

Indium Gallium Nitride thin film was successfully grown on the substrate using an RF magnetron sputter under condition of different substrate temperatures. Various experimental measurements were taken to understand effect of substrate temperature on the structure of thin film and results were analyzed. Grazing mode of XRD results confirmed that thin film has a hexagonal structure with plane for and substrate temperature. It was seen that structural parameters of thin film show a change with substrate temperature change. Reasons were discussed. Strain and stress values in thin film were calculated from experimental results and it was found that all thin film has compressive stress. Morphological parameters of thin film were measured by AFM and it was understood that these properties are varied by changing substrate temperature. Also, growth mode of some thin film was found to be layer-plus-island mode (Stranski-Krastanov growth mode), others was found to be layer by layer growth mode (Frank van der Merwe mode). SEM analysis gives that increasing substrate temperature worsened the surface structure of thin film; it is compatible with and supports XRD results. Compositional values in thin film were found from XPS analysis. In addition to our material, carbon and oxygen have also been obtained from XPS results, as expected. Detailed structural and morphological properties of thin film have been seen to change by changing substrate temperature and we believe this may play an important role in the production of based optoelectronic devices.

Magneto-transport Properties in SrRu0.7Fe0.3O3-δ Epitaxial Thin Film

We investigated the magnetotransport properties in SrRu0.7Fe0.3O3-δ epitaxial thin film synthesized by using pulsed laser deposition. X-ray diffraction (XRD) θ − 2θ and reciprocal space mapping scans showed strong peaks demonstrating high quality. The image of step and terrace at atomic force microscope scan image of the film showed a layer by layer growth mode of the thin film. The resistivity showed a significant decrease by applying magnetic field of 9 T, which could be described in terms of spin dependent scattering. The zero-field resistivity at low temperature (2 K-24 K) was fitted very well with a variable range hopping model. The observed negative magnetoresistance (T = 10 K, H = 9 T) was as high as ~20%.

Thickness-dependent structural characteristics for a sputtering-deposited chromium monolayer and Cr/C and Cr/Sc multilayers.

The interior structure, morphology and ligand surrounding of a sputtering-deposited chromium monolayer and Cr/C and Cr/Sc multilayers are determined by various hard X-ray techniques in order to reveal the growth characteristics of Cr-based thin films. A Cr monolayer presents a three-stage growth mode with sudden changes occurring at a layer thickness of ∼2 nm and beyond 6 nm. Cr-based multilayers are proven to have denser structures due to interfacial diffusion and layer growth mode. Cr/C and Cr/Sc multilayers have different interfacial widths resulting from asymmetry, degree of crystallinity and thermal stability. Cr/Sc multilayers present similar ligand surroundings to Cr foil, whereas Cr/C multilayers are similar to Cr monolayers. The aim of this study is to help understand the structural evolution regulation versus layer thickness and to improve the deposition technology of Cr-based thin films, in particular for obtaining stable Cr-based multilayers with ultra-short periods.

Properties of Pt on Cu(111) revealed by AES, LEED, and DEPES

The investigations of Pt on Cu(111) were carried out to reveal the growth mode and crystalline structure of the adsorbate with the use of Auger electron spectroscopy (AES), low energy electron diffraction (LEED), and directional elastic peak electron spectroscopy (DEPES). Auger signal recorded during the continuous Pt adsorption on Cu(111) at 330 K confirms the layer by layer growth mode. LEED patterns observed at 1ML of Pt show the formation of the compressed adlayer. At higher coverages such as 3ML and 6ML the increase of the lattice constant of the topmost Pt layer, which approaches the bulk value of Pt(111), is noted. DEPES investigations performed for 1ML of platinum indicate the nucleation of adsorbate domains characterized by A/CBA and B/CBA stacking sequences at the Pt/Cu interface, which at higher coverages lead to the nucleation of mutually rotated by 180° Pt islands. Experimental DEPES data were compared to theoretical results obtained with the use of the multiple scattering (MS) calculations for different adsorption geometries including the Pt and Cu intermixing at the interface. The quantitative analysis of the data made by R-factor calculations enabled the determination of Pt domain populations already at 1 ML and 6 ML.

Boosting Electron Extraction in Polymer Solar Cells by Introducing a N-Type Organic Semiconductor Interface Layer

Enhanced power conversion efficiency (PCE) is reported in inverted polymer solar cells (PSCs) when a high electron mobility molecular semiconductor of fluorinated copper phthalocyanine (F16CuPc) is employed on the top of the poly(ether imide) (PEI) buffer layer. The thickness of the F16CuPc and PEI is rearranged to shield the insulating effect of PEI and enhance the electronic coupling between the hydrophobic inorganic ITO and hydrophilic organic active layer. The results demonstrate that the enhanced PCE is attributed to the improved forward charge transfer and the contact resistance decrease by passivating interfacial trap states and defects of ITO surface. The hydrophilic F16CuPc interlayer also regulates the upper organic layer growth mode and morphology so that the back charge recombination is noticeably decreased. As a result, the optimized PSCs indicate the improved PCE of 9.516% relative to 7.147% of the device without F16CuPc.

Skewness and kurtosis of height distribution of thin films simulated by larger curvature model with noise reduction techniques

Time varying skewness (S) and kurtosis (Q) of height distribution of (2+1)-dimensional larger curvature (LC) model with and without noise reduction techniques (NRTs) are investigated in both transient and steady state regimes. In this work, effects of the multiple hit NRT (m>1 NRT) and the long surface diffusion length NRT (ℓ>1 NRT) on the surface morphologies and characteristics of S and Q are studied. In the early growth time, plots of S and Q versus time of the m>1 morphologies show pronounced oscillation indicating the layer by layer growth. Our results show that S=0 and Q<0 at every half layer while S=0 and Q>0 at every complete layer. The results are confirmed by the same plots of the results from the Das Sarma–Tamborenea (DT) model. The ℓ>1 LC model, on the other hand, has no evidence of the layer by layer growth mode due to the rapidly damped oscillation of S and Q. In the steady state, the m>1 and ℓ>1 NRTs affect weakly on the values of S and Q and the mounded morphologies of the film. This lead to the evidence of universality of S and Q in the steady state of the LC models with various m and ℓ. The finite size effect on the values of S and Q is found to be very weak in the LC model. By extrapolating to L→∞, we obtain SL→∞≈0.05 and QL→∞≈−0.62 which are in agreement with the NRTs results.

The Spontaneous Deposition of Au on Pt (111) and Polycrystalline Pt

The development of durable fuel cell catalysts with high activity and low Pt loading is of paramount importance for the fuel cell’s industrial applicability. Conventionally Pt and Pt group metals have been shown to have the highest catalytic activity, however their durability has remained a concern due to CO poisoning and Pt dissolution [1, 2]. This has thusly necessitated the need for mixed metal catalysts, with improved durability, and conserved, or higher activity when compared to bulk Pt. It has been shown that the decoration of catalytically active metals with sub-monolayers of foreign metals can improve catalysts’ durability as well as its activity due to synergistic effects [3-7]. In addition it has been demonstrated that the creation of continuous ultrathin noble metal films on foreign substrates exhibit enhanced electronic and chemisorption properties when compared to the bulk material. This is explained through d-band theory and orbital mixing demonstrated by Norskov et al. [ 8-10 ] . These enhancements have created the need for simple low cost fabrication techniques of these materials, such as spontaneous deposition. Conventional spontaneous deposition involves the adsorption of an ordered ad-layer of a metal complex on a substrate. This adsorption is strong enough to withstand rinsing of the crystal, and then reduction in a solution of the supporting electrolyte. The limited amount of adsorbed complex results in excellent control of the amount of deposited metal, and the spontaneous deposition sequence can then be cycled multiple times in order to generate deposits of desired thicknesses. The spontaneous deposition of Au was previously discovered by this group when demonstrating the surface limited redox replacement of Au on Pt [11], and in this report it will be fundamentally demonstrated. Electrochemically, it will be shown that the spontaneous deposition of Au on Pt operates via a hybrid deposition mode, one that consists of conventional spontaneous deposition as well as an electroless step involving Pt oxidation and [AuCl4]- complex reduction. In addition, via STM, the ordered ad-layer of the [AuCl4]- complex will be demonstrated and it will be shown that deposits generated via spontaneous deposition proceed via a nearly perfect 2-D layer by layer growth mode on both Pt and Au. Finally, it will be shown that the spontaneous deposition of Au on Pt is a suitable strategy for the decoration of Pt with sub-monolayer to nearly perfect multilayer Au films.

(Invited) Pt Monolayers and Submonolayers on Nobel Metal Nanoparticles: Substrate- and Coverage-Depdendent Atomic Structures and Electrocataltyic Activities

Galvanic replacement of underpotentially deposited Cu monolayers (UPD) on noble metal substrates by Pt has been shown a robust strategy to synthesis Pt monolayer catalysts with ideally a 100% Pt utilization efficiency for energy conversion reactions, such as methanol oxidation reaction (MOR) in direct methanol fuel cells. The true atomic structures of the ‘Pt monolayers’ on different noble metal substrates, particularly on nanoscale metal nanoparticles, however, have still remained elusive. By using high resolution (scanning) transmission electron microscopy combined with highly efficient energy-dispersive X-ray spectra mapping, we report here the atomic structures of Pt (sub)monolayers deposited on different noble metal nanoparticles (e.g. Au, Pd, Pt, and Ir, etc.) and at different coverage using the UPD and subsequent galvanic replacement method. Our results reveal that the Pt-substrate interaction has a pronounced influence on the growth mode and atomic structures of the Pt ‘monolayer’, which follows either Volmer-Webber island growth mode or Franck- van der Merwe layered growth mode, leading to different Pt utilization efficiencies and thus different electrocatalytic MOR activities. The nominal coverage of the Pt (sub)monolayers on the noble metal nanoparticles plays an additional role in fine-tuning the atomic structures, Pt utilization efficiency and electrocatalytic MOR activities. Our results provide important atomistic insights into a rational design of Pt (sub)monolayer catalysts with high Pt utilization efficiency and high catalytic activities.

Growth techniques used to develop CDS/CDTE thin film solar cells: a review

The method used to grow thin film CdS/CdTe solar cells has been described. Electronic material layers usually grow in three different modes; layer-by-layer growth mode, layer and cluster growth mode (Stransky-Krastanov) and cluster formation growth mode. Techniques such as molecular beam epitaxy (MBE), metal organic chemical vapour deposition (MOCVD) called melt growth or Bridgman are well known as high quality semiconductor growth techniques. One of the limitations of these techniques is the inability for manufacturing macro-electronic devices (~area 1m 2 ) such as photovoltaic (PV) panels and large area display devices. To grow large area thin film (semiconductors), growth techniques such as close space sublimation (CSS), electrodeposition (ED), sputtering, spray pyrolysis etcetera have been tested and employed. This paper reviews in depth most of these techniques with more emphasis on the electrodeposition method because of it is simplicity and low cost. Keywords : Growth Techniques, CdS, CdTe, Thin Films, Solar Cells.