Chloride Multi-Source Epitaxial Growth of CuGaS2 and CuGaSe2

A novel epitaxial growth technique–chloride multisource epitaxial growth–for ternary compounds is described. Beams of the source vapors, CuCl, Ga and S (Se), are supplied into a high-purity nitrogen or hydrogen atmosphere of 10 -4 Torr. The c -axis epitaxial growths of CuGaS 2 and CuGaSe 2 are attained on GaAs (100) substrates at 600–620°C. The effects of the CuCl/Ga supply ratio on the layer growth are examined. The epitaxial layers are strained compressively along the c -axis by the thermal expansion mismatch between the grown layer and the substrate.