Unfiltered cathodoluminescence map of the surface of a nitride semiconductor wafer. The dark spots indicated by the blue arrows correspond to individual dislocations intersecting the wafer surface whilst the banding reveals a periodic change in the incorporation of point defects during crystal growth.

A semiconductor is a generic term for materials that have electrical conductivity between conductors (like copper and aluminum), and insulators (like rubber and glass). There are few elemental semiconductors, but there are widespread commercial applications in microelectronics and photovoltaics. However, other elements may be combined to form compound semiconductors—alloys with properties of a semiconductor, e.g., GaAs, GaN, CdTe, and (many) others. Despite the high cost of manufacture, compound semiconductors form the basis of many modern devices, including light-emitting diodes, power transistors, and detectors, because of their attractive fundamental material properties, including efficient light emission across the ultraviolet, visible and infrared portions of the electromagnetic spectrum.

The light emission from semiconductors can be used to reveal the functional properties of the material that directly impact the performance of many commercial devices. The ability of the cathodoluminescence (CL) technique to analyze the light emission at a spatial resolution commensurate with the device feature size and to correlate that information with the composition, size, shape, and crystal structure makes CL a highly valuable technique. For example, the functional properties of compound semiconductor materials and devices depend critically on the sample structure, compositional uniformity, and defect concentrations and distribution, all of which can be revealed in detail using CL. For these reasons, CL is used widely in process development or material and device characterization.

Experiment briefs and application notes

Cathodoluminescence as a technique for inspection, metrology, and failure analysis of microLED processing Spectroscopic analysis of ultra-wide bandgap semiconductors Complete understanding of light emission with nanoscale spatial resolution
An example of why it is so important to correlate the structural and optical properties of semiconductor nanorods directly Nano-cathodoluminescence reveals the effect of indium segregation on the optical properties of nitride semiconductor nanorods Mapping the electronic bandgap of semiconductor compounds with milli-electron volt accuracy
Nano-cathodoluminescence enables the design of light-emitting diodes with higher efficiencies A nanoscale cathodoluminescence study of nitride semiconductor nanowires Revealing the spatial distribution of phases in perovskite solar cells for the development of high efficiency