= Type-I band alignment
A <type-I band alignment> confines <Electrons> and <electron holes> together: its inner <conduction band> edge is lower, its <valence band> edge higher.<Nobel Lecture: Quasielectric fields and band offsets: teaching electrons new tricks by Herbert Kroemer>[§IV, Figs. 6–8, pp. 786–787]{ref}
In the chosen <band offset> example, the <Electron> barrier is $0.6$, while the <electron hole> barrier is $0.4$. A hole's excitation <energy> is measured downward from a <valence band> maximum: reversing that convention would incorrectly make the two barriers appear to repel opposite carriers. An electrostatic shift $-q\phi$ moves both electron <energy band> edges together; changing the <band gap> also changes their separation. Thus material composition supplies a control beyond the <electric potential> $\phi$ alone.
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