Confirming your mental model matches the mathematical reality. How to Use the Solution Manual Effectively
It covers the "why" behind semiconductor physics before diving into the "how."
Today, the 5th edition is considered a classic "vintage" era of electronics education. While newer editions (like the 7th and 8th) have updated the tech to smaller nanometer scales, the 5th Edition Solution Manual
You can find the manual hosted as part of academic material collections. Check the unm-ieee ECE Material repository for a downloadable version.