In order to explain diffusion and drift across the depletion zone of a p-n junction, semiconductor theory relies on holes which act as a positive charge equivalent of electrons. As positive charge carriers, holes need to physically move and be involved in random collisions to produce the Brownian motion required to explain diffusion. Any lack of hole-movement, or even the required type of hole-movement, represents a major problem for semiconductor theory. The Pauli Exclusion Principle indicates that, if an atomic orbital is occupied by an electron of one-half spin state, the orbital may only be shared by an electron of opposite spin (i.e. negative one-half spin). An atomic orbital is full when it is occupied by a pair of electrons of opposite spin, with no more electrons able to enter it until one of the pair vacates the orbital. This paper looks at the possibility and implications of extending the electron spin concept to ‘free’ electrons within semiconductors, with positive and negative charge carriers simply being electrons with opposite spin. The existence of two physically different charge carriers in the form of opposite-spin electrons, which requires only minor terminology adjustments to semiconductor theory, provides a better explanation of the formation and nature of electric fields; capacitor charge/discharge; and micro/radio wave generation. Also, the concept of electric currents being the one-way movement of generic electron charge carriers, which totally ignores electron spin, is challenged.