Photoluminescence study of critical thickness of pseudomorphic quantum wells grown on small area mesa stripes

Pseudomorphic In0.18Ga0.82As single quantum wells (QWs) have been grown by metalorganic chemical vapor deposition (MOCVD) on patterned substrates with mesa sizes of 3.5 μm oriented along [110] and [11̄0] directions. Using a post-growth masking technique, photoluminescence (PL) has been used to characterize the optical properties of the as-grown QWs. Our results show the increase of the critical thickness by about 50% for growth on [110] undercut mesa as compared with that on the planar substrate due to the discontinuous growth behavior and no increase of critical thickness of [11̄0] oriented mesas due to the continuous growth behavior and outdiffusion of In from the facet wall of the groove to the mesa top.