The band edge shift and splitting in an orthorhombically strained Si (OS-Si) layer grown on the sidewall of a compressively strained SiGe (CS-SiGe) alloy is calculated in terms of model-solid theory. Both the valence and conduction band edges of the OS-Si are predicted to be lower than those of CS-SiGe. Compared with tensily strained Si grown on a relaxed SiGe alloy, the conduction band offset between OS-Si and CS-SiGe is smaller, while the valence band offset is larger. (C) 2002 Elsevier Science Ltd. All rights reserved.