Mapping the electronic band gap of semiconductor compounds with milli-electron volt accuracy
Gatan instrument used
Gatan’s cathodoluminescence (CL) products enable optically-coupled transmission electron microscopy (TEM) to reveal and correlate nanoscale structural, optical, and electronic properties of materials.
Background
The energy band gap (Egap) is an important feature of semiconductors that determines their use in electronics and optoelectronics applications. Through control of a semiconductor’s band gap, scientists and engineers can design novel devices and optimize device designs. However, with the explosion in nanotechnologies, determining Egap at a meaningful spatial resolution is increasingly complex. The device has a graded Egap formed by sulfur (S) diffusion into the CdTe absorber during thermal processing. Here we demonstrate how to reveal the change in Egap by analyzing the photons emitted due to radiative recombinations after the sample is excited by the focused electron beam of a TEM.
