In the semiconductor industry scientists take advantage of diffusion to “dope” or introduce atoms into a silicon wafer to change its conductive properties. The lesson simulates the diffusion of a gas phase substance (ammonia) into a solid substrate (gelatin) and compares the lab model of diffusion to the doping process of silicon wafers. Students will examine how diffusion occurs and explore how the electrical properties of semiconductors are developed. This lesson uses only commonly available substances.
This lab is designed to help students understand one aspect of semiconductor manufacture: selective layering.
This scanning electron microscope image shows an indium arsenide (InAs) nanowire field-effect transistor.
"Exploring Materials - Graphene" is a hands-on activity in which visitors use tape and graphite to make graphene and test the conductivity of graphite. They learn that graphene is a single layer of carbon atoms arranged in a honeycomb pattern. There are two versions of this activity, one that uses an LED to test the conductivity and one that uses a buzzer.