Bulk-suppressed and surface-sensitive Raman scattering by transferable plasmonic membranes with irregular slot-shaped nanopores

Abstract Raman spectroscopy enables the non-destructive characterization of chemical composition, crystallinity, defects, or strain in countless materials. However, the Raman response of surfaces or thin films is often weak and obscured by dominant bulk signals. Here we overcome this limitation by placing a transferable porous gold membrane, (PAuM) on the surface of interest. Slot-shaped nanopores in the membrane act as plasmonic antennas and enhance the Raman response of the surface or thin film underneath. Simultaneously, the PAuM suppresses the penetration of the excitation laser into the bulk, efficiently blocking its Raman signal. Using graphene as a model surface, we show that this method increases the surface-to-bulk Raman signal ratio by three orders of magnitude. We find that 90% of the Raman enhancement occurs within the top 2.5 nm of the material, demonstrating truly surface-sensitive Raman scattering. To validate our approach, we quantify the strain in a 12.5 nm thin Silicon film and analyze the surface of a LaNiO3 thin film. We observe a Raman mode splitting for the LaNiO3 surface-layer, which is spectroscopic evidence that the surface structure differs from the bulk. These results validate that PAuM gives direct access to Raman signatures of thin films and surfaces

Teen mothers who are daughters of teen mothers: Psychological intergenerational dimensions of early motherhood

Introduction: Researchers have shown that being a daughter of a teenage mother is a risk factor regarding the possibility of having early, unprotected sexual intercourse and of falling pregnant. The experiences of young mothers in such situations and the aspects of intergenerational transmission in the mother–daughter relationship have not been well investigated. Objectives: This study analyses the experience of motherhood in young mothers (18–20 years at the time of the interview/15–16 at the time of their pregnancy) who are daughters of teen mothers themselves from the psychodynamic perspective of intergenerational transmission. Methods: Six young mothers from Southern Italy were selected and interviewed. A semi-structured interview was used to explore the early experience of pregnancy and motherhood and their relationship with their own mothers. The interviews were analysed through Interpretative Phenomenological Analysis (IPA). Results: Five superordinate themes emerged: I didn't want, I didn't see and I didn't feel; Adolescence? I suddenly became a mother; History repeats itself again and again; Confused Spaces and How difficult is coming into the world? Conclusion: Adolescent mothers, who themselves are daughters of teen mothers, seem to have difficulty in representing the meanings associated with their experience of pregnancy and motherhood. A lack of narrative transmission of the experience of pregnancy from mothers to daughters emerged. The implications for research and social policies will be discussed