Fundamental difference in the mechanisms of transformation of InAs nanostructures due to indium segregation on flat and patterned GaAs surfaces

Applied Surface Science. 2025. Vol. 700. Article 163211.

Solodovnik M., Balakirev S., Ivan S. Makhov, Dukhan D., Chernenko N., Kirichenko D., Shandyba N., Eremenko M., Natalia V. Kryzhanovskaya, Alexey E. Zhukov

Despite the rapid growth in the number of studies devoted to quantum dot (QD) formation on patterned substrates,
segregation effects that have a significant impact on the properties of QD-based heterostructures remain
largely unexplored. In this paper, we focus on the influence of segregation under different capping regimes on the
optical properties of various InAs/GaAs nanostructures: QDs and ultrathin quantum wells on a flat surface and
QDs on a patterned surface. For the first time, a fundamental difference is shown in the mechanisms of nanostructure
transformation on the flat and patterned surfaces. On the flat surface, an increase in the capping rate
leads to a redshift in the photoluminescence spectra, indicating a pronounced correlation between characteristics
of InAs nanostructures before and after capping. In the case of the patterned surfaces, suppression of lateral
transport of segregating indium atoms caused by an increase in the capping rate, on the contrary, results in an
effective reduction in QD sizes due to the lack of compensation of indium losses via vertical transport, leading to
a blueshift in the photoluminescence spectra. We experimentally demonstrate the possibility of obtaining lowdensity
InAs/GaAs QDs on the patterned surfaces emitting in the range of up to 1100 nm at 5 K without
visible formation of a wetting layer. Our results highlight the importance of competition between the outflow of
indium atoms due to segregation and their inflow due to localization of the material in nanoholes when creating
nanostructures with localized QDs and devices based on them.

Keywords: квантовые точки, nanostructures, quantum dots, Наноструктуры, молекулярно-пучковая эпитаксия, molecular beam epitaxy

Publication based on the results of: Источники оптического излучения на основе квантово-размерных структур А3В5 для интегральной оптоэлектроники: исследование физических явлений, разработка конструкции и методов формирования (2027)