Near-surface defects in hydrogen-plasma-exposed InGaAs/GaAs quantum well structures

摘要

The near-surface damage introduced in InGaAs/GaAs heterostructures during hydrogen plasma exposure is investigated by photoluminescence (PL) spectroscopy and transmission electron microscopy. Multiple quantum well structures are used to monitor the depth of plasma- and/or hydrogen-related defects below the surface. It is shown that hydrogen plasma exposure introduces defects at depths which exceed the ion ranges in implanted solids by more than an order of magnitude. The introduction of {111} hydrogen platelets in GaAs during plasma exposure is also demonstrated fOr the first time. Although a correlation is found between the depth distributions of these platelets and the extent of induced defects indicated by PL, it is shown that these extended defects are not responsible for the reduction in optical efficiency of the near-surface material. Rather, point-like defects resulting from ion bombardment and/or hydrogen itself are suggested to be the cause of the deterioration of the optical quality of the material.