Cadmium Telluride

Cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe, or CZT) are semiconductors with applications in solar cells and particle detection. For the solar cell market, low-cost synthesis techniques must be developed. In semiconductor alloys determination of the concentration of alloy constituents is of considerable importance to understand process dynamics during synthesis. In this example we will use cadmium zinc telluride (CZT) to show how the Zn content of CZT can be mapped using photoluminescence (PL) spectra. 

CZT is often grown using the Bridgeman technique in large boules. CZT typically has a weak PL signal and normally displays only a single well-defined peak. Klar’s microscopes are very sensitive, and using our robust modeling of the spectral features, small changes in PL peak energy can be detected. 

For this example, a slice of a CZT boule was mapped using a Klar Mini Pro instrument with 532 nm excitation, and the resulting PL spectra were fitted using a single bigaussian function. Figure 1 shows an example spectrum and fit and Figure 2 shows a spatial map of the peak energy. In these fits, available parameters are the emission peak energy, peak amplitude and peak width. We are presently concerned with the peak energy only. Read More….