The fabrication of n- and p-vertical advanced heterostructure MOS (VAHMOS) transistors involves pseudomorphic growth of SiGe alloys on Si as well as on relaxed buffer layers. SiGe layers grown by molecular beam epitaxy (MBE) and chemical Vapor deposition (CVD) have been investigated with optical and electrical spectroscopy with respect to material quality, composition and defect concentration. Modulation doped samples grown by CVD showed higher photoluminescence (PL) efficiency compared to undoped samples with similar layer structures and growth conditions. PL measurements together with X-ray analysis of samples grown by MBE with a high Ge fraction (30-50%) indicated no disorder and no relaxation. Photocurrent (PC) measurements and deep level transient spectroscopy (DLTS) were used to identify various defects giving rise to electrically active deep levels.