Microstructural, optical and electrical properties of Cl-doped CdTe single crystals

Microstructural, optical and electrical properties of Cl-doped CdTe crystals grown by the low pressure Bridgman (LPB) method were investigated for four different doping concentrations (unintentionally doped, 4.97 × 10¹⁹ cm⁻³, 9.94 × 10¹⁹ cm⁻³ and 1.99 × 10²⁰ cm⁻³) and three different locations within the ingots (namely, samples from top, middle and bottom positions in the order of the distance from the tip of the ingot). It was shown that Cl dopant suppressed the unwanted secondary (5 1 1) crystalline orientation. Also, the average size and surface coverage of Te inclusions decreased with an increase in Cl doping concentration. Spectroscopic ellipsometry measurements showed that the optical quality of the Cl-doped CdTe single crystals was enhanced. The resistivity of the CdTe sample doped with Cl at the 1.99 × 10²⁰ cm⁻³ was above 10¹⁰ Ω.cm.