CuInS₂ Thin Films Deposited by ALD

At present, chalcopyrites are widely studied as absorber materials for efficient, low‐cost, thin film solar cells. The growth of CuInS 2 thin films by atomic layer deposition (ALD) is studied here. CuInS 2 films are grown on glass, TCO glass (SnO 2 :F‐coated glass), and TiO 2 substrates under pressures in the range 2–10 mbar, with temperatures between 350 °C and 500 °C, using CuCl, InCl 3 , and H 2 S as precursors. The influence of the process conditions on the properties of the material is examined, and the deposition temperature and the pulse length of the precursors are found to be the decisive parameters. The morphology and the composition of the films are investigated using scanning electron microscopy (SEM), X‐ray diffraction (XRD), Rutherford backscattering (RBS), and Raman spectroscopy (RS). Depending on the process conditions, CuInS 2 single phase, Cu‐poor (mixture of CuInS 2 and CuIn 5 S 8 ), or Cu‐rich (mixture of Cu x S and CuInS 2 ) phases are formed.