The nanoHUB has a nice Introduction to Semiconductor Devices web page/tool that that covers the following topics:

• Crystal structures and lattices
• Band models and structure
• Bulk semiconductors
• PN junctions
• Bipolar Junction transistors
• MOS capacitors
• MOSFETs

This introduction as part of the Assembly of Basic Applications for Coordinated Understanding of Semiconductors (ABACUS) tool used to integrate lectures, simulators, and labs into a common platform.