Black Phosphorus-Based Reusable Biosensor Platforms for the Ultrasensitive Detection of Cortisol in Saliva.

A black phosphorus (BP)-based reusable biosensor platform is developed for the repeated and real-time detection of cortisol using antibody-conjugated magnetic particle (MP) structures as a refreshable receptor. Here, we took advantage of the low-noise characteristics of a mechanically exfoliated BP-based field-effect transistor (FET) and hybridized it with anti-cortisol antibody-functionalized MPs to build a highly sensitive cortisol sensor. This strategy allowed us to detect cortisol down to 1 aM in real time and discriminate cortisol from other hormones.

Nanoscale mapping of edge-state conductivity and charge-trap activity in topological insulators.

We report the nanoscale mapping of topological edge-state conductivity and the effects of charge-traps on conductivity in a BiSe multilayer film under ambient conditions. In this strategy, we applied an electric field perpendicular to the surface plane of BiSe a conducting probe to directly map the charge-trap densities and conductivities with a nanoscale resolution. The results showed that edge regions had one-dimensional characteristics with higher conductivities (two orders) and lower charge-trap densities (four orders) than those of flat surface regions where their conductivities and charge-traps were dominated by bulk effects.

Nanoscale Mapping of Carrier Mobilities in the Ballistic Transports of Carbon Nanotube Networks.

Much progress has been made in the nanoscale analysis of nanostructures, while the mapping of key charge transport properties such as a carrier mobility remains a challenge, especially for one-dimensional systems. Here, we report the nanoscale mapping of carrier mobilities in carbon nanotube (CNT) networks and show that charge transport behaviors varied depending on network structures. In this work, the spatial distribution of localized charge transport properties such as mobilities and charge trap densities in CNT networks were mapped via a scanning noise microscopy.