Laboratory for Electrical Sensor Studies

Laboratory for Electrical Sensor Studies

Investigation of thin-film and bulk structures for gas sensors by means of electrical measurements. This includes evaluation of resistance under changes in humidity, temperature and gas environment, testing and calibration of sensors, as well as the development and optimisation of materials based on oxide and chalcogenide semiconductors and dielectrics.

Man in a white lab coat sitting at a monitor with control software next to a large laboratory installation

Description of Activities

  • Research activities for the characterisation of the sensing properties of various materials and structures;
  • Calibration and testing of finished sensors

Description of the Service

The laboratory carries out electrical studies of various thin-film and bulk structures used in gas sensors, including:

– Measurement of electrical resistance as a function of changes in the environment, e.g. changes in humidity, temperature and the concentration of various gases;

– Testing and calibration of finished sensor devices;

– Development, improvement and optimisation of thin-film and bulk structures  based on oxide and chalcogenide semiconductor and dielectric materials.

Equipment

Metal chamber with flanges and a viewing window, connected to coloured cables and a CONDENSER TANK

Kenosistec KGAS4S gas sensor test system, simulating the ambient environment in a small volume. The system enables the sensing response of the materials and structures under study to be tested under various conditions simulating the environment, such as humidity, temperature and the concentration of various gases, by measuring the change in the resistance of the sample as the parameters of the environment are varied. The system is equipped with 6 gas lines for supplying different types of gas to the working chamber at a controlled humidity of 10 to 90%. By means of precision controllers, the gas concentration can be regulated within the range of 1 to 5000 ppm. The laboratory currently has the following test gases available: CO2, NO2, NH3. Measurements can be performed at temperatures from room temperature up to 400oC with an accuracy of ±2oC. The working chamber can be pre-evacuated to 10-5 mbar. Electrical measurements are performed with two Keithley 6487/E SMU picoammeters, at a constant voltage of up to 500V and currents down to

10-12 A. The set-up allows testing and calibration of  unencapsulated and unbonded sensor devices.

Wheeled laboratory rack labelled KENOSISTEC KS GAS 4S, a white cabinet with a window and a monitor
Open chamber with metal flanges on a KENOSISTEC KS GAS 4S rack and a monitor with control software

Research

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Access to the Laboratory for Electrical Sensor Studies

The Laboratory for Electrical Sensor Studies is part of the research infrastructure of the National Centre of Excellence “Mechatronics and Clean Technologies” and is located on the Geo Milev campus. Requests for access and for joint research are therefore handled centrally — see Contact. In addition, a full overview of the Centre’s other laboratories is available on the Infrastructure and Laboratories page.

The equipment for electrical sensor studies was set up under project BG16RFPR002-1.014-0006, funded by the Programme “Research, Innovation and Digitalisation for Smart Transformation” 2021–2027, co-financed by the European Union through the European Regional Development Fund.