Control of surface states for III-V semiconductor quantum structures and its application to novel optical devices

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The purpose of this study is to investigate the interaction mechanism between surface states and confined levels in III-V compound semiconductor quantum structures and to control the surface properties by use of ultrathin silicon interface control layr (SiICL) for fabrication of novel optical devices. The main results obtained are listed below :(1) It was found that the photoluminescence (PL) intensity from the near-surface quantum well (OW) with the surface-to-well distance of 5nm, was reduced by a factor of 1000 as compared with that from the reference QW located deeply inside. We revealed that this phenomenon is caused by strong interaction between the quantized states in near-surface QW and surface states. Acomplete recovery of PL intensity was achieved by use of Si-ICL based passivation technique.(2) X-ray photoelectron spectroscopy analysis revealed that there were no oxidized and nitrided phase of semiconductor surface at the passivation film/semiconductor interfaces.(3) By applying the Si-ICL passivation method, a nearly complete recovery of PL intensity was achieved with an observed maximum recovery factor of 400 for the InGaAs quantum wires. The quantum wires passivated with SiICL showed strong PL intensity even at room temperature.(4) The Si-ICL passivation technique was successfully applied to passivation of side walls of InGaAs quantum wires fabricated by wet etching process.(5) Detailed computer simulation pointed out that a clear passivation effects can be explained by substantial reduction of surface states by Si-ICL based passivation technique