Spectroscopy of growth islands in GaAs/In0.1Ga0.9As/AlAs double-barrier structures from photoluminescence and resonant tunneling studies

Photoluminescence spectroscopy is used to investigate interface roughness e ffects on electron and hole tunneling through GaAs/In0.1Ga0.9As/AlAs double -barrier tunneling structures. Typical quantum-well photoluminescence spect ra present a splitting of 8 meV due to interface roughness and island forma tion in the quantum well. The states of these islands are selectively popul ated by electrons and holes by applying bias and changing the photon excita tion intensity. Carrier transfer mechanisms between islands are clearly ide ntified as well as intersubband scattering in a sequential tunneling pictur e. The measurement of activation energies as a function of bias provides an estimate for the electron density in resonant tunneling condition for diod es showing up islands at the interfaces. The possibility of observing growt h island effects in I(V) characteristics is also carefully discussed. [S016 3-1829(99)06231-1].