Dirac (1928), (http://rspa.royalsocietypublishing.org/content/royprsa/126/801/360.full.pdf) explained the negative-energy solutions of his equations as holes in a sea of electrons. The concept seems very similar to that of hole conduction in semi-conductor physics.
Commonly, the transistor (also the semiconductor diode) is explained in terms of electrons and holes. According to Wikipedia the transistor was patented 1925 by Julius Edgar Lilienfeld, but not realized experimentally.
Did he build on the concept of a Dirac sea to theorize the transistor? Less specifically: Did the concept of the Dirac Sea influence (lead to) thedevelopment of semiconductors like the transistor?
Or, in view of the order of the dates: Was Dirac inspired by semiconductor physics?