Discrete monolayer light emission from GaSb wetting layer in GaAs

Distinct light emission peaks from monolayers of GaSb quantum wells in GaAs were observed. Discrete atomic layers of GaSb for the wetting layer prior to quantum dot formation give rise to transition peaks corresponding to quantum wells with 1, 2, and 3 ML. From the transition energies the authors were able to deduce the band offset parameter between GaSb and GaAs. By fitting the experimental data with the theoretical calculated result using an 8×8 kp Burt's Hamiltonian along with the Bir-Picus deformation potentials, the strain-free (fully strained) valence band discontinuity for this type-II heterojunction was determined to be 0.45 eV (0.66 eV).