Dislocation structure and photoluminescence of partially relaxed SiGe layers on Si(001) substrates

Abstract

The dislocation structure and photoluminescence of partially relaxed Si 1−x Ge x layers on Si(001) substrates were studied to reveal the contribution from dislocations localized in different regions of the heterostructure (SiGe layer, SiGe/Si interface, Si substrate) to the dislocation-related PL. The D1 and D2 lines were ascribed to products of dislocation reactions in intersection sites. The known dependence of the D4 line spectral position on the Ge content is not observed, which is explained by the effect of elastic strain in the SiGe/Si heterostructure.

Dislocation photoluminescence in silicon crystals of various impurity contents

“…The sensitivity of D1 line to oxygen, the formation of helical dislocations during oxygen precipitation in silicon [9] and nucleation of copper precipitates near the edge-type jogs on screw dislocations [11] suggest that the jogs associated with D1 line might be localized on screw dislocations and those with D2 line -on 60° dislocations. Some ratios between the intensity of D1 and D2 lines (I D1 and I D2 , respectively) available in the literature for samples with definite type dislocations evidence for this suggestion: the ratio I D1 >I D2 is fulfilled for preferential screw [12] or edge dislocations [13] and the ratio I D2 >I D1 -for 60° dislocations [14]. The ratio I D2 >I D1 is also fulfilled in our samples in which 60° dislocations dominate (Fig.…”

Direct-Gap Photoluminescence from a Si-Ge Multilayer Super Unit Cell Grown on Si0.4Ge0.6

“…The The energy separations (∼30 meV, as seen from Tables I and II), and general appearance of these peaks is reminiscent of PL that has been attributed to the presence of various dislocation defects (i.e., the four so-called D lines) in Si [13][14][15][16] and SiGe alloys. 17,18 The observed stronger PL features are in the right energy range for dislocations, if one extrapolates their possible line positions from those of silicon. For example, see the "D1" and "D2" lines discussed by Sauer et al for silicon.…”

Defect studies in strain-relaxed Si$_{1-x}$Ge$_{x}$ alloys

“…There has been an extensive study of dislocation-related photoluminescence in Si [5][6][7] and Si 1−x Ge x alloys [8][9][10]. From an experimental point of view, D1/D2 and D3/D4 bands have similar origins due to similarities in their optical properties.…”