Exciton binding energies in GaInAs/InP quantum wells determined by thermally modulated photoluminescence

Abstract

Atmospheric pressure organometallic vapor phase epitaxy has been used for the growth of single InP/GaInAs/InP quantum wells with atomically abrupt interfaces. This has allowed wells as thin as 10 Å to be grown which give sharp photoluminescence (PL) spectra at 10 K. PL and thermally modulated PL have been used to distinguish band-to-band and exciton luminescence transitions allowing an estimation of the exciton binding energy. For the first time, the qualitative trend of an increase in exciton binding energy with decreasing well width for thick wells followed by a distinct maximum and a sharp decrease in binding energy with decreasing well width for very thin wells has been observed. The maximum binding energy of approximately 17 meV is found to occur for a nominal well width of approximately 13 Å.