Monitoring the operation of a graphene transistor in an integrated circuit by XPS

Abstract

a b s t r a c tOne of the transistors in an integrated circuit fabricated with graphene as the current controlling element, is investigated during its operation, using a chemical tool, XPS. Shifts in the binding energy of C1s are used to map out electrical potential variations, and compute sheet resistance of the graphene layer, as well as the contact resistances between the metal electrodes. Measured shifts depend on lateral positions probed, as well as on polarity and magnitude of the gate-voltage. This non-contact and chemically specific characterization can be pivotal in diagnoses.

Lab-based operando x-ray photoelectron spectroscopy for probing low-volatile liquids and their interfaces across a variety of electrosystems

“…This technique, especially under AC actuation, has been developed and extensively used by our group. [9][10][11] While DC excitation during data acquisition provides steady state information, AC excitation helps to understand the dynamics of electrical potential developments. Real time observation of fast processes occurring in a time of a few milliseconds is difficult to observe by conventional XPS studies under laboratory conditions.…”

X-ray Photoelectron Spectroscopy with Electrical Modulation Can Be Used to Probe Electrical Properties of Liquids and Their Interfaces at Different Stages

“…This task is traditionally performed either ex situ, by comparing the surface composition before and after a specific process is applied, − or in operando, by interrogating the surface of the sample via a designated process. , Understanding electrical and electrochemical processes and/or devices under operating conditions is vital to the development of new technologies. Operando XPS with the application of an external electrical voltage bias, in either the dc or ac form, during data acquisition can be very useful in the investigation of such devices because of its ability to provide electrical and chemical information about the sample, which has been extensively used by our group. − Extending it to the investigation of liquids has been relatively slow, mostly because of vacuum requirements, which has been successfully overcome by using multiple pumping stages and efficient electron optics. Hence, nowadays ambient pressure XPS systems are available at both synchrotron facilities and via laboratory-based instruments. − A parallel investigation route has been pursued by using liquids with negligible volatility and sufficient electrical conductivity, mainly, ionic liquids and polymer electrolytes, enabling researchers to probe electrochemical properties and/or reactions with chemical specificity, rendering a wealth of electrochemical information. − …”