Tunneling-Controlled Photoluminescence in Nonresonantly Coupled Single Quantum Wells

Electron plus hole tunneling is observed optically by photoluminescence in In sub (0.53) Ga sub (0.47) As/InP coupled-single quantum wells. We study a set of samples each with 100 and 60angstroms wide wells separated by barriers of varying thicknesses L sub b. For L sub b 40angstroms, the two excitonic emission lines thermalize with activation energies demonstrating directly combined tunneling of electrons and holes.