In a semiconductor diode, electrons flow from:

A diode is a two-terminal component that acts as a one-way valve for electricity. When dealing with electron flow, which moves from negative to positive, the electrons enter the diode at the negative terminal, known as the cathode, and exit at the positive terminal, known as the anode. It is important to note that conventional current is often described as flowing from anode to cathode (positive to negative), which is the exact opposite of actual electron flow. Options like 'base to collector' and 'source to drain' are incorrect because they refer to the terminals of bipolar junction transistors and field-effect transistors, not diodes.