Formation of coupled three-dimensional GeSi quantum dot crystals

Abstract

Coupled three-dimensional GeSi quantum dot crystals (QDCs) are realized by multilayer growth of quantum dots (QDs) on patterned SOI (001) substrates. Photoluminescence spectra of these QDCs show non-phonon (NP) recombination and its transverse-optical (TO) phonon replica of excitons in QDs. With increasing excitation power, peak energies of both the NP and TO peaks remain nearly constant and the width of the TO peak decreases. These anomalous features of the PL peaks are attributed to miniband formation due to strong coupling of the holes and the emergence of quasioptical phonon modes due to periodic scatters in ordered GeSi QDs.

Optical properties of individual site-controlled Ge quantum dots

“…[1][2][3][4] A main motivation for studying the optical properties of this material system is the prospect of efficient light emitters and single photon sources in the near infrared spectral range for monolithic integration into a silicon device platform. 5 Recent progress in site-controlled growth of SiGe QDs on pre-patterned Si(001) substrates, [6][7][8][9][10] and their commensurable embedding into photonic crystal slabs 11 has opened a unique route toward deterministic positioning of individual SiGe QDs in photonic crystal resonators. Yet, optical studies were mainly performed on ensembles of SiGe QDs, which cause broadening of the photoluminescence (PL) lines due to variations in QD size [12][13][14][15][16] and local composition.…”

Influence on miniband structure of size variations in regimented InAs/GaAs quantum dots arrays

“…1 Other efforts have pursued the order by increasing the quantum dot density using Stranski-Krastanov methods. 2 Examples of different techniques to obtain periodic nanostructures could be found elsewhere, [3][4][5][6][7] and some works show that theoretical and experimental results on this topic are converging. 8 As a result of these efforts, two-and three-dimensional arrangements have been obtained experimentally nowadays with a decent degree of accuracy.…”

Effect of strain on the electronic and optical properties of Ge–Si dome shaped nanocrystals

“…[6][7][8][9][10][11][12][13][14][15][16][17][18] Ge/Si based nanostructures are of interest due to their compatibility with the existing silicon-based technology. Furthermore, Ge/Si nanostructures with various shapes (domes, wire, lens, and pyramids) have been fabricated and integrated in optical and electrical devices using advanced fabrication techniques such as molecular beam epitaxy (MBE), 19 self-assembly, [20][21][22] and chemical vapor deposition (CVD). 8 These devices exhibit size dependent characteristics and show potential for future devices such as thin-film field effect transistors, 7 flash memory, 8,10 DotFETs, 23 photodetectors, 24 solar cells, 25,26 and quantum computers.…”

“…[29][30][31][32][33] Researchers have recently been successful in fabricating high quality Ge/Si NCs of different lateral dimensions and shapes in both single and multiple layers. 19,[34][35][36][37] Of the various experimentally observed NC shapes, hut-shaped and dome-shaped Ge/Si NCs have unique electronic and optical properties. 38 Dome-shaped Ge/Si NCs with the curved bounding facets can relieve strain more efficiently compared to the hut, pyramid, or ring shaped NCs.…”