In-situ sub-angstrom characterization of laser-lubricant interaction in a thermo-tribological system.

Laser-lubricant interaction has been a critical reliability issue in a thermo-tribological system named heat-assisted magnetic recording, one of the next generation hard disk drive solutions to increasing data storage. The lubricant response under laser irradiation and the subsequent lubricant recovery are crucial to the system's reliability and longevity, however, they cannot be diagnosed locally and timely so far. Here, we propose a thermal scheme to in-situ characterize the mechanical laser-lubricant interaction.

Protocol for nanoscale thermal mapping of electronic devices using atomic force microscopy with phase change material.

In this protocol, we present a facile nanoscale thermal mapping technique for electronic devices by use of atomic force microscopy and a phase change material GeSbTe. We describe steps for GeSbTe thin film coating, GeSbTe temperature calibration, thermal mapping by varying heater power, and thermal mapping by varying heating time. The protocol can be applied for resolving surface temperatures of various operational microelectronic devices with a nanoscale precision.

Precise nanoscale temperature mapping in operational microelectronic devices by use of a phase change material.

The microelectronics industry is pushing the fundamental limit on the physical size of individual elements to produce faster and more powerful integrated chips. These chips have nanoscale features that dissipate power resulting in nanoscale hotspots leading to device failures. To understand the reliability impact of the hotspots, the device needs to be tested under the actual operating conditions.

Boosting contact sliding and wear protection via atomic intermixing and tailoring of nanoscale interfaces.

Friction and wear cause energy wastage and system failure. Usually, thicker overcoats serve to combat such tribological concerns, but in many contact sliding systems, their large thickness hinders active components of the systems, degrades functionality, and constitutes a major barrier for technological developments. While sub-10-nm overcoats are of key interest, traditional overcoats suffer from rapid wear and degradation at this thickness regime.

Electrostatically Tunable Adhesion in a High Speed Sliding Interface.

Contact hysteresis between sliding interfaces is a widely observed phenomenon from macro- to nanoscale sliding interfaces. Most such studies are done using an atomic force microscope (AFM) where the sliding speed is a few μm/s. Here, we present a unique study on stiction between the head-disk interface of commercially available hard disk drives, wherein the vertical clearance between the head and the disk is of the same order as in various AFM-based fundamental studies but with a sliding speed that is nearly 6 orders of magnitude higher.

Voltage assisted asymmetric nanoscale wear on ultra-smooth diamond like carbon thin films at high sliding speeds.

The understanding of tribo- and electro-chemical phenomenons on the molecular level at a sliding interface is a field of growing interest. Fundamental chemical and physical insights of sliding surfaces are crucial for understanding wear at an interface, particularly for nano or micro scale devices operating at high sliding speeds. A complete investigation of the electrochemical effects on high sliding speed interfaces requires a precise monitoring of both the associated wear and surface chemical reactions at the interface.

A simple microfluidic aggregation analyzer for the specific, sensitive and multiplexed quantification of proteins in a serum environment.

Portable and low-cost platforms for protein biomarker detection are highly sought after for point of care applications. We demonstrate a simple microfluidic device for the rapid, electrically-based detection of proteins in serum. Our aggregation analyzer relies on detecting the protein-induced aggregation of sub-micron particles, using a one-step procedure followed by a fast, particle-by-particle measurement with a very high count rate.

High-speed discrimination and sorting of submicron particles using a microfluidic device.

The size- and fluorescence-based sorting of micro- and nanoscale particles suspended in fluid presents a significant and important challenge for both sample analysis and for manufacturing of nanoparticle-based products. Here, we demonstrate a disposable microfluidic particle sorter that enables high-throughput, on-demand counting and binary sorting of submicron particles and cells using either fluorescence or an electrically based determination of particle size. Size-based sorting uses a resistive pulse sensor integrated on-chip, whereas fluorescence-based discrimination is achieved using on-the-fly optical image capture and analysis.

Andreev current-induced dissipation in a hybrid superconducting tunnel junction.

We have studied hybrid superconducting microcoolers made of a double superconductor-insulator-normal metal tunnel junction. Under subgap conditions, the Andreev current is found to dominate the single-particle tunnel current. We show that the Andreev current introduces additional dissipation in the normal metal equivalent to Joule heating.

Electron and phonon cooling in a superconductor-normal-metal-superconductor tunnel junction.

We present evidence for the cooling of normal-metal phonons, in addition to the well-known electron cooling, by electron tunneling in a superconductor-normal-metal-superconductor tunnel junction. The normal-metal electron temperature is extracted by comparing the device current-voltage characteristics to the theoretical prediction. We use a quantitative model for the heat transfer that includes the electron-phonon coupling in the normal metal and the Kapitza resistance between the substrate and the metal.