Formation of Schottky electrode for CdTe radiation detector

We investigated the effect of plasma treatment on the surface composition of CdTe and the electrical properties of Schottky contact using Al, Ti and In. The composition of the initial CdTe surface is Te-rich due to Br-methanol etching. We propose the plasma treatment method to remove the Te-rich layer. From X-ray photoelectron spectroscopy measurement, it is found that the plasma treatment can remove the Te-rich layer. The rectification properties of Al and Ti Schottky contacts formed on the plasma-treated surfaces are improved. Barrier heights of plasma-treated Schottky contacts are larger than nonplasma-treated contacts. Ideality factor is also improved by using plasma treatment. In gamma-ray spectrometry, a high-energy resolution of 1.8 keV FWHM at 59.5 keV is obtained from plasma-treated Al Schottky contact.