Low-Temperature Growth and Doping of CdTe Epilayers on CdTe Substrates in a Remote-Plasma-Assisted MOCVD System for Nuclear Radiation Detector Applications

Abstract

Homoepitaxial growth and n-type impurity doping of CdTe layers at low substrate temperatures were carried out for their applications in nuclear radiation detector fabrication. The grown epilayers were characterized by scanning electron microscopy, photoluminescence and Hall measurements. Highly conductive iodine doped layers could be obtained at a substrate temperature of 150 °C, and these layers were found to be more suitable for radiation detector applications than other layers grown at higher substrate temperatures. The surface morphology of these homoepilayers was not very smooth, however, distinct edge emission and deep level emission bands were observed on the PL spectra at 20 K. A diode-type radiation detector fabricated using this low temperature growth and doping technique, exhibited very good rectification property with a very low value of reverse bias leakage current and an excellent nuclear radiation detection property.