the.com/bandgap
the energy toll a material charges an electron before it lets it conduct.
means it is the gap between the valence band and conduction band in a material, the minimum energy an electron needs to jump from bound to free.
from emerged from quantum theory of solids in the 1920s-30s, when physicists like felix bloch and rudolf peierls modeled electrons in crystals as waves and found their allowed energies split into bands with forbidden zones between.
metalshave zero bandgap, electrons roam free always
insulatorsgap so wide room temperature cant bridge it
silicon value1.1 electron volts, the chip industry's magic number
temperature shrinks ithotter materials have slightly smaller bandgaps
for instance
silicon — 1.12 eV gap powers basically every computer chip made
gallium nitride — 3.4 eV gap enables blue leds, nobel prize 2014
diamond — 5.5 eV gap makes it a near perfect insulator
germanium — 0.67 eV gap, the original 1947 transistor material