Effects of spacer thickness on optical properties of stacked Ge/Si quantum dots grown by chemical vapor deposition

Abstract

Photoluminescence investigations on stacked Ge/Si dots with different spacer thicknesses are presented. According to the emission energy shift in the Ge dots, we found that a thinner spacer layer will lead to remarkable Ge–Si intermixing during the stacking of the Ge/Si dots. Such material intermixing not only shallows the dot potential depth, but also softens the sharpness of the dot/spacer interface. In addition, the temperature of photoluminescence quenching also varies with the spacer thickness. Finally, we point out some important factors that are relevant to the room-temperature luminescence efficiency of stacked Ge/Si quantum dots.

Morphological evolution of self-assembled SiGe islands based on a mixed-phase pre-SiGe island layer grown by ion beam sputtering deposition

“…The previous experimental findings revealed that the areal density, size uniformity, and spatial distribution of the SiGe islands grown via the Stranski-Krastanov (S-K) mode play an important role in controlling the luminescence properties of lasers and the detected wavelength of infrared photodetectors [1,3,4]. Different recipes have been proposed to enhance the island density, i.e., the boron (B) or carbon (C)-induced growth [5,6] and the low-temperature growth [7], etc.…”

SiGe nanostructures with self-assembled islands for Si-based optoelectronics

“…Besides the growth temperature, the thickness of the Si spacer layer (d Si ) in multilayer structures is the other parameter affecting the localization of the charge carriers in structures with Ge(Si) islands and their probability of radiative recombination [6,29,30]. On one hand, the increase of the Si spacer thickness leads to the decrease of elastic strain in the multilayer structure.…”

Investigation of deformations and strain fields in silicon matrix structures embedded with vertically stacked Ge(Si) self-assembled islands

“…This effect has been described theoretically in Refs. [19][20][21]23, and 24 as well as demonstrated by many growth experiments; 1,2,22,25,26 however, it has not been measured or shown directly so far.…”

“…Investigation of deformations and strain fields in silicon matrix structures embedded with vertically stacked Ge(Si) self-assembled islands D. A. Pavlov, 1,a) A. I. Bobrov, 1 A. V. Novikov, 2 D. S. Sorokin, 1 N. V. Malekhonova, 1 A. V. Pirogov, 1 D. E. Nikolitchev, 1 The information on the distribution of distortions and strains in GeSi heteronanosystems is fundamentally important for their design and creation. Studies in this field use a number of techniques, [1][2][3][4][5][6][7][8][9] among which one of the most informative is the cross-section high resolution transmission electron microscopy (HRTEM).…”

“…Studies in this field use a number of techniques, [1][2][3][4][5][6][7][8][9] among which one of the most informative is the cross-section high resolution transmission electron microscopy (HRTEM). At present, there are two main TEM techniques which allow us to get directly detailed information on values and the distribution of distortion fields in crystal nanostructured objects: the nano-beam electron diffraction (NBED) 3,7 and the geometric phase analysis method (GPA).…”