General on FET2D

The set of FET2D study objects, FET2DAtomisticParameterExtraction, FET2DSentaurusModelCalibration and FET2DSentaurusDeviceCharacteristics, facilitate modelling of 2D-channel FET devices using custom materials, by combining the functions of QuantumATK and Sentaurus Workbench. By starting from atomic scale modelling in FET2DAtomisticParameterExtraction, a much broader range of materials (and combinations thereof) can be investigated for potential devices. Sentaurus Workbench can then be used to perform device characterization with customizable device designs such as being single-/double-gated or for different channel lengths, which can be specified in DeviceSetupParameters.

Typical calculation time of an individual calculation step - parameter extraction, model calibration or device characteristic - is about 2 days for a single channel monolayer. Model calibration step can take longer, especially if the calculation doesn’t converge to a certain value.

Jobmanager setup

In order to run Sentaurus Workbench through Nanolab, the following definitions need to be either exported or source via a script on the Environment tab of the Machine Settings for a chosen machine in Jobmanager:

  • STROOT - The root folder of a Sentaurus Workbench installation.

  • STRELEASE - The release version of Sentaurus Workbench to use.

  • STDB - The working directory that Sentaurus Workbench should use, where Sentaurus Workbench settings and calculation results will be stored.

  • LD_LIBRARY_PATH - The path(s) to libraries needed for Sentaurus Workbench.

  • SWB_SITE_SETTINGS_DIR - The setting for, e.g., job queuing that Sentaurus Workbench should use.

  • LM_LICENSE_FILE - The license file that Sentaurus Workbench should use.

Also ensure that STROOT/bin is in the PATH variable, e.g.

PATH=$STROOT/bin:$PATH; export PATH

Next, SWB_QUEUE_NAME needs to be defined in the Export statements with a queue name specific to the HPC cluster running Sentaurus Workbench, e.g.

SWB_QUEUE_NAME=sge:all

where sge:all is an example queue name.

Finally, the following workaround needs to be applied in the Job specification commands field:

# SWB machine, skip mpiexec.
MPIEXEC_EXECUTABLE=''
N=''

This is necessary because by default, QuantumATK scripts are executed using an MPI executable, but this is not compatible with running Sentaurus Workbench from within a QuantumATK script, hence we omit the MPI executable for any machine that is intended for this purpose. This need to separate machines intended for running Sentaurus Workbench is also the reason why parameter extraction cannot be chained together with model calibration and device characterization in the FET2D plugin.

Caution

It is not recommended to run QuantumATK scripts on a machine designated to run Sentaurus Workbench, as there will be no parallelization of the calculation due to the omission of the MPI executable.

As always, it is a good idea to Run Diagnostics on the Diagnostics tab of the Jobmanager to ensure the settings are correct.