N-type CdS layer prepared by shallow chemical bath deposition on a 370 × 470 mm2 glass substrate

The n-type layer plays an important role in the fabrication of CuInGaSe2 solar cells in terms of solar cell efficiency and production cost. Chemical bath deposition is commonly used to prepare n-type layers. However, uniformity, coverage, and cost issues presented by the method must be solved prior to its application in mass production. A technique called shallow chemical bath deposition was employed to grow an n-type CdS layer on a 370 mm × 470 mm glass substrate. This technique used a shallow bath for higher thermal gradients, while using a shaker to mix solution. As a result, the homogeneous nucleation was suppressed and large area uniformity could be achieved. UV–visible NIR spectrophotometry, scanning electronic microscopy, and X-ray diffraction were employed to characterize the quality of the thin film obtained. The experimental results showed that shallow chemical bath deposition could be an excellent candidate for chemical bath deposition technique.

► Shallow chemical bath deposition (SCBD) technique is advantageous in terms of materials consumption.
► Conformal and dense CdS thin film was prepared on 370 × 470 mm2 soda-lime silicate glass.
► The SCBD technique resulted in uniform CdS film with good coverage.
► CdS film has high transmission with band gap variation within 0.05 eV.