What is a photoconductive semiconductor switch (PCSS)?

A photoconductive semiconductor switch, or PCSS, is a device concept based on a semiconductor material that conducts electricity when it is turned on with light. Before the light turns it on, it does not conduct electricity. In most types of PCSS devices, the electrical conduction ceases or rapidly decays once the light source is turned off. In other cases the electrical conduction might continue, which is called a "latch-on" effect.

There are many applications for PCSS devices, some which benefit from a fast turn-on and/or turn-off response times and others that benefit from a slow turn-on and/or turn-off response times.

A major benefit of GaN and other wide bandgap semiconductors for PCSS applications is the potential for high voltage and high power switching. Indeed, Kyma's KO-Switchâ„¢ is the highest voltage and fastest GaN PCSS device on the market, we believe.

Such benefits and many more details about PCSS devices are described nicely in a recently published article called "Wide Bandgap Extrinsic Photoconductive Switches" by J.S. Sullivan of Lawrence Livermore National Laboratory (LLNL) - that report is publicly available and can be downloaded at https://e-reports-ext.llnl.gov/pdf/759551.pdf.