III-V族半導体量子ドットの配列・形状制御(<小特集>ナノ結晶)

概要

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Nano-probe assisted techniques for site-controlled quantum dots (SCQDs) with a nm-level site precision have been developed for suppression of dot-size fluctuation, thus achieving an excellent optical device performance such as femtosecond-level optical switching. An SCQD was first demonstrated by using an in situ EB (electron beam) process combined to a self assembled (S-K mode InAs/GaAs epitaxy. A two-dimensional sub-pm-pitch array of InAs SCQDS with sub-100 nm diameters was successfully formed. Existence of partially missing SCQDS was suppressed by a new technique of sulfur passivation prior to the S-K mode epitaxy. The site precision of the SCQD was drastically improved to a nm level for the first time by using an in situ STM scanning tunneling microscope probe technique. Implementation of an array-pitch and dotdiameter reduction to several tens nm by this technique was attributed to novel nano-deposit and nano-hole formation processes. As a novel technique for a shape-control of QDs, height-control of InAs quantum dots on GaAs surfaces by in-situ AsBr_3 etching and MBE was also introduced and results at the preliminary experiment have been described. This work was supported by NEDO within the framework of the Femtosescond Technology Project.
日本結晶成長学会の論文
2001-10-12