Temperature difference in close-spaced sublimation (CSS) growth of CdTe thin film on ultra-thin glass substrate

Doroody, Camellia; Rahman, Kazi Sajedur; Abdullah, Siti Fazlili; Harif, Muhammad Najib; Rosly, Hasrul Nisham; Tiong, Sieh Kiong; Amin, Nowshad

doi:10.1016/j.rinp.2020.103213

Cited by 22 publications

(3 citation statements)

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“…Available CdTe structures are namely zinc blende (cubic) or wurtzite (hexagonal) form [3]. Having a high absorption coefficient (>10 4 cm −1 ) and simplicity of deposition, the light to be converted to electricity in a few micrometer thin CdTe layers which allowed fabrication on various type of substrates i.e., glass, foils, polymers, and ultra-thin glass (UTG) for lightweight and bendable configurations [4]. Soda-lime glass (SLG) is the most popular glass used in thin-film fabrication; however, because of its low thermal stability and transmittance, borosilicate glass has become a choice for superstrate CdTe thin films.…”

Section: Introductionmentioning

confidence: 99%

Impact of CdCl2 Treatment in CdTe Thin Film Grown on Ultra-Thin Glass Substrate via Close Spaced Sublimation

2021

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In this study, close-spaced sublimation (CSS) grown cadmium telluride (CdTe) thin films with good adhesion to 100 µm thin Schott D263T ultra-thin glass (UTG) were investigated. Cadmium chloride (CdCl2) treatment in vacuum ambient was executed to enhance the film quality and optoelectrical properties of CdTe thin film. The post-deposition annealing temperature ranging from 360–420 °C was examined to improve the CdTe film quality on UTG substrate. Various characterization techniques have been used to observe the compositional, morphological, optical, as well as electrical properties. Scanning electron microscopy (SEM) verified that the CdTe morphology and grain size could be controlled via CdCl2 treatment temperature. Energy Dispersive X-Ray Analysis (EDX) results confirmed that the annealing temperature range of 375–390 °C yielded the stoichiometric CdTe films. UV-Vis analysis estimated the post-treatment bandgap energy in the range of 1.39–1.46 eV. Carrier concentration and resistivity were obtained in the order of 1013 cm−3 and 104 Ω-cm, respectively. All the experimental results established that the CdCl2 treatment temperature range of 390–405 °C might be considered as the optimum process temperature for the deposition of CdTe solar cell on UTG substrate in close-spaced sublimation (CSS) method.

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Section: Introductionmentioning

confidence: 99%

Impact of CdCl2 Treatment in CdTe Thin Film Grown on Ultra-Thin Glass Substrate via Close Spaced Sublimation

2021

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“…Several methods, like the Scherer formula, Williamson-Hall plot, etc., are available to calculate the diffraction peak profile. However, comparison of final grain size from different methods is complex, due to the difference in results, the order of magnitude and basis in each system and only estimation of grain size can be provided [40]. XRD presents the size of the crystallite, while SEM calculates the physical grains.…”

Section: Resultsmentioning

confidence: 99%

An In-Depth Analysis of CdTe Thin-Film Deposition on Ultra-Thin Glass Substrates via Close-Spaced Sublimation (CSS)

2022

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This study evaluated the impact of the deposition pressure on the formation of cadmium telluride (CdTe) thin films on ultra-thin (100 µm) Schott glass substrate at high temperature (T > 450 °C) by Close-Spaced Sublimation (CSS) technique. CdTe thin films were grown under the pressure range of 1 Torr to 200 Torr to explore the impact of deposition pressure on CdTe thin-film properties. The microstructural, compositional and optoelectrical characteristics were examined. X-ray Diffraction (XRD) analysis revealed the cubic phase crystallite CdTe films with (111) preferential orientation. Scanning Electron Microscopy (SEM) demonstrated that the CdTe morphology and grain size could be regulated via the deposition pressure, whereby maximum grain growth was detected at low pressure (1–5 Torr). The thickness of CdTe films was reduced from 6 µm to 1.5 µm with the rise in deposition pressure. Moreover, the optical direct energy gap was derived in the range of 1.65–1.69 eV for the pressure value of 200 Torr to 1 Torr. Carrier density and resistivity were found to be in the order of 1013 cm−3 and 104 Ω cm, respectively. The experimental results suggest that the pressure range of 1–5 Torr may be ideal for CSS-grown CdTe films on flexible ultra-thin glass (UTG) substrates.

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“…[7], chemical bath deposition, [8], pulsed laser deposition [9], close-range sublimation [10], electro deposition [11], thermal evaporation [12] and Electron beam evaporation [13]. Nevertheless, the difficult duty is to obtain a stoichiometic CdTe films to better design the absorber layer in the solar cell structure, since defects and/or impurities generated during the deposition process will affect the optoelectronic properties of prepared thin films, thereby changing the efficiency of the solar cells [14,[15][16][17]. Also, it is reported that the electrical and optical properties of CdTe thin films are tuned by doping with appropriate dopant (Bi, Co, Ag, Cu, In and Mo) into CdTe semiconductor lattice, which enhances the efficiency of solar cells [18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Microstrucral, Optical and Electrical Characteristics of Cu-doped CdTe Nanocrystalline Films for Desinging of Absorber Layer in Solar Cell Applications

Alzaid

Hadia

El-Hagary

et al. 2021

Preprint

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This paper reports the microstrcure, optical and electrical characteristics of undoped and Cu doped CdTe nanostructured thin films prepared on glass substrates by electron beam evaporation technique. The Crystallographic study of X-ray diffraction shows that CdTe and Cu doped CdTe films crystallize in the form of a cubic zinc blende structure. Microstructure analysis reveals that as the Cu doping level increases, the average crystallite size increases, while the microstrian decreases due to the improvement of the crystallinty, thereby reducing defects. XRD and AFM investigations confirmed the nanostructure characteristic of undoped and Cu doped films. It was found that the optical band gap energy increases from 1.485 eV to 1.683 eV as the Cu concentration increases from 0 wt. % to 10 wt. %, which may be related to the Burstein-Moss effect. The refractive index is calculated from the Swanepoel envelope method and found to decrease with the increase of the Cu doping due to the decrease in the prolizability. Similarly, the extinction coefficient decreases with the increase of Cu in CdTe matrix. The dc electrical conductivity is found to increase with increasing Cu doping, which is attributed to the increase in the grain size, thereby reducing the scattering of the grain boundary. Furthermore, two conduction mechanisms of the carrier transport in nanostrcutured undoped and Cu doped CdTe films were observed. The low temperature dependence of the conductivity of undoped and Cu doped CdTe nanostructured films is explained based on Mott’s variable range hopping conduction mechanism model (VRH). Interestingly, the calculated values of hopping distance R, the hopping energy W and the the density of states at the Fermi level N(EF) are consistent with the Mott's VRH. Finally, Hall effect measurements show that all the films have p- type conduction behavior. Besides, the results show that as Cu doping level increases, the carrier concentration and the Hall mobility increase due to the decrease in grain boundary scattering with the increase in grain size. Accordingly, it can be concluded that by increasing the Cu doping level in the CdTe film, the conductivity is increased, thereby improving the performance of the CdTe absorber layer in the solar cell structure.

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Temperature difference in close-spaced sublimation (CSS) growth of CdTe thin film on ultra-thin glass substrate

Cited by 22 publications

References 50 publications

Impact of CdCl2 Treatment in CdTe Thin Film Grown on Ultra-Thin Glass Substrate via Close Spaced Sublimation

Impact of CdCl2 Treatment in CdTe Thin Film Grown on Ultra-Thin Glass Substrate via Close Spaced Sublimation

An In-Depth Analysis of CdTe Thin-Film Deposition on Ultra-Thin Glass Substrates via Close-Spaced Sublimation (CSS)

Microstrucral, Optical and Electrical Characteristics of Cu-doped CdTe Nanocrystalline Films for Desinging of Absorber Layer in Solar Cell Applications

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