High quality InAs quantum dots grown on patterned Si with a GaAs buffer layer

Abstract

Ordered and dense InAs quantum dots grown on patterned Si(100) with a thin GaAs buffer layer have been investigated by transmission electron microscopy and electron energy loss spectroscopy. {111} faceted InAs quantum dots with good crystallinity were observed on top of the underlying GaAs buffer layer. It was revealed that the GaAs buffer layer and the lateral expansion of InAs have played key roles in releasing the misfit strain between InAs and Si and suppressing the formation of lattice defects in InAs quantum dots. These results suggest a possible pathway for the strain relaxation in the formation of quantum dots.

Crystalline structures and misfit strain inside Er silicide nanocrystals self-assembled on Si(001) substrates

“…Figures 2(a To investigate the lattice mismatch between the Er silicide nanowire and the Si substrate along the ErSi 2 [0001] direction, inverse FFTs were performed by masking 0002 * spots of ErSi 2 and Si 220 * spots in the FFT pattern of the HRTEM image, and the results are shown in figure 3(c). From the figure, ErSi 2 {0002} and Si{220} atomic planes can be observed and can be used to study the nature of the defects by examining the numbers of extra atomic planes [13]. For the region containing the entire ErSi 2 /Si interface (marked with a solid and a dashed rectangle), one can observe 45 ErSi 2 {0002} planes and 46 Si{220} planes (by counting the white lines), namely the lattice mismatch of (46 − 45)/46 = 2.2% exists.…”

Nanostructured hybrid material based on highly mismatched III–V nanocrystals fully embedded in silicon

“…However, the heteroepitaxial growth of III–V nanostructures directly on silicon is quite challenging due to substantial crystalline defect density . These structural defects are closely related to carrier dynamics in the nanostructures and as a result, the presence of such defects in the III–V nanostructures will destroy the light emission .…”

Pre‐patterned silicon substrates for the growth of III–V nanostructures

“…Nevertheless, heteroepitaxial growth typically introduces a substantial crystalline defect density 18–21. As a result, the presence of high‐density threading dislocations due to the lattice mismatch and the formation of antiphase boundaries due to the polar non‐polar nature of the III–V/IV semiconductor system propagating through the active material will become a non‐radiative recombination centre, which will destroy the light emission 22–24. Growth on pre‐patterned substrates could result in reducing or eliminating such defects due to size effect and effective lateral stress relaxation related to the presence of facet edges and sidewalls 25–28.…”

“…Therefore, we have carried out considerable work in order to develop and optimize an etching process suitable for the purpose of over‐growth on pre‐patterned silicon. In recent years, some research efforts have also been made to realize the growth of III/V QDs on pre‐patterned silicon substrates using SiO 2 as a mask which show encouraging results 24, 38. For such fabrications, several lithographic techniques are in use for pre‐patterning silicon substrates, such as focused ion beam (FIB), scanning probe techniques and electron beam lithography (EBL).…”