This project develops a measurement system for finding the thermal properties of samples by measuring frequency dependent signals of heat sources and temperature sensors attached to the sample.  Thermal diffusivity is commonly used in the temperature dependent characterization of materials used in power electronics such as silicon carbide and diamond, common semiconductors such as silicon and gallium arsenide, and thermoelectric materials used in cooling and power generation applications.  In this project, we will explore the phase shift of time dependent signals along with impedance spectroscopy to determine if this can be used in characterizing the thermal diffusivity and thermal conductivity of the samples measured.  During this 10 week program, the student, together with Tim Hogan, will conduct these measurements on a series of samples, analyze the data and compare the results with values found in the published literature.  The results will be presented at the MSU-wide undergraduate research conference

Scientific goals:   

• Mount platinum resistors on opposite faces of the sample in a vacuum chamber and use one of the resistors as a heat source, and the other as a temperature sensor.  Measure the time dependent signals of the heat source, and the temperature sensor and determine the phase shift between the signals.
• Analyze the data collected to find the thermal diffusivity of the sample and compare the results with values found in published literature.
• Measure the temperature dependent impedance spectroscopy of the heat source to see if thermal resonance in the sample can be monitored and used as an alternative method for thermal diffusivity measurements.

Student learning goals:

• Basic thermal heat wave propagation and measurement techniques
• Instrument control and data acquisition methods
• Data analysis for temperature dependent thermal diffusivity measurements