Drift of Schottky Barrier Height in Phase Change Materials.

Phase-change memory (PCM) devices have great potential as multilevel memory cells and artificial synapses for neuromorphic computing hardware. However, their practical use is hampered by resistance drift, a phenomenon commonly attributed to structural relaxation or electronic mechanisms primarily in the context of bulk effects. In this study, we reevaluate the electrical manifestation of resistance drift in sub-100 nm Ge2Sb2Te5 (GST) PCM devices, focusing on the contributions of bulk vs interface effects. We employ a combination of measurement techniques to elucidate the current transport mechanism and the electrical manifestation of resistance drift. Our steady-state temperature-dependent measurements reveal that resistance in these devices is predominantly influenced by their electrical contacts, with conduction occurring through thermionic emission (Schottky) at the contacts. Additionally, temporal current-voltage characterization allows us to link the resistance drift to a time-dependent increase in the Schottky barrier height. These findings provide valuable insights, pinpointing the primary contributor to resistance drift in PCM devices: the Schottky barrier height for hole injection at the interface. This underscores the significance of contacts (interface) in the electrical manifestation of drift in PCM devices.

Prelacteal feeding practice and maintenance of exclusive breast feeding in Bihar, India - identifying key demographic sections for childhood nutrition interventions: a cross-sectional study.

Background:  Exclusive breastfeeding (EBF) during the first six months of life is considered a high impact, but low-cost, measure for improving nutritional status, and reducing morbidity and mortality among children. However, providing prelacteal feed to a newborn, a widely practiced custom in rural India, is a major barrier to the practice of EBF.  The present study evaluated the association between provision of prelacteal feeding and continuation of EBF among children up to 3 months age in Bihar, a resource-poor Indian state. Methods: Data from four rounds of a population-based multi-stage sampling survey, conducted in 8 districts of Bihar between 2012 and 2013, were used for the present analysis. Using simple and adjusted logistic regression modelling, we tested the association of providing prelacteal feeding with two outcome measures - 1) giving only breastmilk during the last 24 hours, and 2) exclusively breastfed (EBF) since birth (excluding the first 3 days of life). Results: Among 10,262 children for whom prelacteal feeding data was available, 26% received prelacteal feeding. About 55% mothers reported that their children were exclusively breastfed, whereas 82% mothers provided only breastmilk to their children during the previous 24 hours. Children who received prelacteal feeding had approximately 60% lesser odds of being breastfed exclusively during the previous 24 hours [AOR = 0.39(0.33-0.47)] and 80% lesser odds of receiving continued EBF since birth [AOR = 0.20(0.17-0.24)]. Conclusions: Frontline workers (FLW) provide nutritional counselling to mothers and children of rural India. In order to improve uptake of EBF, the families practicing prelacteal feeding should be identified early and educated on the harmful effects of prelacteal feeding for EBF and subsequently on infant health. Midwives/nurses at the public and private facilities as well as the home birth attendants should also be made aware about the negative effects of prelacteal feed.

Measurement of carrier mobility in silicon nanowires.

We report the first direct capacitance measurements of silicon nanowires (SiNWs) and the consequent determination of field carrier mobilities in undoped-channel SiNW field-effect transistors (FETs) at room temperature. We employ a two-FET method for accurate extraction of the intrinsic channel resistance and intrinsic channel capacitance of the SiNWs. The devices used in this study were fabricated using a top-down method to create SiNW FETs with up to 1000 wires in parallel for increasing the raw capacitance while maintaining excellent control on device dimensions and series resistance. We found that, compared with the universal mobility curves for bulk silicon, the electron and hole mobilities in nanowires are comparable to those of the surface orientation that offers a lower mobility.