Impact of an air barrier on the electron states of etch-released quantum heterostructures

This work investigates the effect of the quantum well interface on the photoluminescence (PL) spectrum. The samples consist of an MBE (molecular beam epitaxy) grown InP/InGaAs heterostructure with two sets of a multiquantum well structure (MQW) and a single quantum well (SQW) symmetrically placed around a sacrificial layer. All are attached to a common anchor where the heterostructure is still in its pristine state; only the bottom heterostructure is present in the exposed well region next to the cantilevers. The transfer matrix method yields transition wavelengths for the SQW in the unprocessed buried case and exposed case. The electron states in the MQW structure form a mini band at the top of the quantum well and are not affected by the nature of the interface.