Conceptual understanding of the P-N diode among undergraduate electrical engineering students

Abstract

Probing students' conceptual understanding and misconceptions of key engineering concepts is a rich area of research. Given the importance of modern electronics in today's world, it is essential for many engineers, particularly device designers from electrical engineering, to have a robust conceptual knowledge of how electronic devices work. The P-N junction diode is the building block of more advanced semiconductor devices. This exploratory study investigates the representations that students use to describe the behavior of a P-N junction diode. Participants were 3rd year students enrolled in a required introductory course in semiconductor physics. Each student participated in a one hour individual semi-structured "think-aloud" interview where he/she had to conceptually solve problems related to P-N junction diodes. Although these semiconductor physics courses aim to develop foundational knowledge for future device design engineers; the results of this study suggest that even successful upper division students majoring in electrical engineering may not have a good conceptual grasp of key concepts related to the diode by the end of the course. For example, many could not correctly differentiate between the linear (or resistive) behavior of an N-N junction and the non-linear behavior of a P-N junction diode. Half of the students in this study did not use their previous knowledge including current-voltage (I-V) curves to perform reality checks. The students struggled with both the macro-level behavior of a P-N junction diode and the underlying micro-level phenomena. By investigating the roots of students' challenges, this study supports the need for new teaching approaches to facilitate better conceptual understanding in introductory semiconductor physics courses.