CuInS2 Thin Films Deposited by ALD

Abstract
At present, chalcopyrites are widely studied as absorber materials for efficient, low‐cost, thin film solar cells. The growth of CuInS2 thin films by atomic layer deposition (ALD) is studied here. CuInS2 films are grown on glass, TCO glass (SnO2:F‐coated glass), and TiO2 substrates under pressures in the range 2–10 mbar, with temperatures between 350 °C and 500 °C, using CuCl, InCl3, and H2S 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, CuInS2 single phase, Cu‐poor (mixture of CuInS2 and CuIn5S8), or Cu‐rich (mixture of CuxS and CuInS2) phases are formed.