Effects of deposition temperature and CdCl2 annealing on the CdS thin films prepared by pulsed laser deposition

Abstract

a b s t r a c tPulsed laser deposition (PLD) technique is suitable for the deposition of high-quality compound semiconductor thin films, and has been widely developed in recent years. However, pulsed laser deposition of CdS films has rarely been reported. In this work, we prepared CdS thin films using PLD. The effects of growth temperature on the PLD-CdS thin films were studied towards high-performance CdS/CdTe thin film solar cells. Results showed that the CdS film prepared at 400 C has the best crystallinity and optical transmittance, while 200 C is more suitable for the window layer of CdTe solar cells due to the highest energy conversion efficiency and the best short-wavelength response. CdCl 2 annealing treatment was also employed on the 200 C-deposited and 400 C-deposited PLD-CdS layer. Annealing treatment further enhanced crystallinity, and obviously enlarged the grain size. Optical transmittance spectra showed that the band gap of the CdS films increased after annealing. Fermi level of CdS films shifted closer to the conduction band from XPS analysis. CdTe solar cells with annealed windows obtained further improved performance, including higher short-circuit current, open-circuit voltage and energy conversion efficiency.

In Situ Low-Temperature Chemical Bath Deposition of CdS Thin Films without Thickness Limitation: Structural and Optical Properties

“…Consequently, when these two parameters are optimized, the problem of supersaturation of the solution, observed in the literature [23,[30][31][32][33], can be avoided. Moreover and contrary to the reported works [24,29,30,34], this technique allows growing in situ films, in a single technological step, at low temperature and without any postdeposition annealing treatment. Thus, the process developed in this work is considered as a relevant candidate when seeking to deposit CdS films on flexible substrates used in the embedded electronic systems.…”

“…Hereafter, this method was adopted to prepare the CdS thin films presented in this study. According to previous works, the quality of CdS thin films prepared by the CBD technique depends strongly on various synthesis parameters such as the deposition time [23], the bath and annealing temperature [24,25], the ammonia agent complex [26], and the concentrations of the chemical reagents [27], Unfortunately, when seeking to synthesize CdS thin films by CBD, two major problems are generally encountered: (i) the postannealing treatment, which is a classical essential step for film crystallinity improvement, usually inducing a strong Cd thermal diffusion [28] and prevents the CdS deposition to be extended to flexible substrates [29], and (ii) the film thickness limitation, which is attributed to the solution supersaturation phenomenon [23,30]. To overcome these problems, the synthesis process has been carried out in several runs.…”

Spin-coated nickel doped cadmium sulfide thin films for third harmonic generation applications

“…The CdS thin films have been extensively explored by numerous techniques, for instance, sol-gel dip-coating [14], spray pyrolysis [15], chemical vapor deposition (CVD) [16], sputtering [17], electrodeposition [18], pulse laser deposition [19] and chemical bath deposition [20]. With all the techniques to coat CdS thin films, the sol-gel spin-coating method stands out because it offers several advantages like simplicity, low cost, and its ability to generally obtain uniform films with good adherence and reproducibility [21].…”

Synthesis of Thin Films of Sulfides of Cadmium, Lead and Copper by Chemical Bath Deposition

“…The PbS is mainly used as an infrared detector in various fields has been used mainly as an infra-red detector in another diverse field [11][12][13][14][15]. On the other hand, the CdS material shows a direct band gap between 2.42 and 2.53 eV [16][17][18][19][20][21][22][23][24][25]. The CdS material was used as a pigment as well as for solar cells optical window; cadmium sulfide is a semiconductor II-VI type which is mainly useful in optoelectronic devices and some researchers reported that it has low conductivity of 10.8 (Ω cm) −1 .…”