A novel double-heterojunction PnpN optical thyristor is presented in w
hich both the center n-layer and the center p-layer are completely dep
leted at equilibrium. This structure is an extremely attractive optoel
ectronic switch, because it allows the marriage of two usually incompa
tible features: speed and optical sensitivity. The speed results from
the fact that our PnpN-structure can be reset to equilibrium, from any
point on the current-voltage characteristics, in less than 10 ns by m
eans of a simple negative anode-to-cathode voltage pulse. The optical
sensitivity is a direct consequence of the center n- and p-layers bein
g completely depleted of free carriers at equilibrium. We show experim
ental evidence of this reset operation by studying the dynamics of the
free-carrier extraction from the center n- and p-layers.