The course is not well-organized, lacks clarity, and packed with too many details. The instructor just assumes all of the students have learned semiconductor in undergrad, and goes into extremely detailed discussion without first reviewing the basics. Students are basically lost in a sea of equations, and cannot see the physical picture clearly.
The instruction is not very helpful. The instructor likes to make unnecessary eye contacts to the students, and likes to ask "any question" at the very beginning of class. He likes to slip through a lot of equations in his slides very quickly, and tells jokes for the rest of the time.
Moreover, students are occupied by too many exams (TWO midterms for a graduate class!) . The homework is also very puzzling, and often have important information missing in the questions, and in this case students have to make up the information themselves.

I never write reviews about professors but I feel like this one was well deserved. Took him for both 221A/221B. All of his lectures consist of him telling stories or "jokes" for most of the class. Very little explanation of the physics behind transistor operation, instead he shows a lot of complicated differential equations in all of his slides. Glances over them with some hand waves and arrives at solutions leaving usually leaving the class confused. Every time a question is asked he gives a very abstract explanation and then tells you to go home and think about it. It sucks that this course material is so important for PWE students and only has this teacher to teach it!
Exam averages in the 50s with a spread all over the place. I feel like he gave out the final grades by the mere fact if he likes you or remembers you or if you are in his student research group. Frustrating class, but still necessary for anyone who needs semiconductor background just be prepared to learn the material on your own and for very hard exams.

Avoid if you can, the course should be named "Mathematics of semocondutors" not "PHYSICS of semiconductors" Lecture notes are basically mathematical derivations of every single equations with minimum physics. One more thing to note is that your grade will depend on whether you have the past exam scripts, not how much you know or understand.