Solution
= Solution
A standard substitutional acceptor choice is \b[Mg on a Ga site]: a group-II atom replaces group III, leaving one fewer valence <electron>. Its size is sufficiently compatible with the cation sublattice to make substitution plausible. This identifies the intended acceptor chemistry; actual <hole> density also depends on activation, incomplete ionization and compensation. Size and valence rules alone do not guarantee a shallow, fully ionized acceptor.