Compensation and defect passivation processes in polycrystalline CdTe: Cl layers

Abstract

An extensive optical spectroscopy investigation of Polycrystalline Cl doped CdTe layers brings new insights into the compensation and passivation processes typical of such structurally imperfect materials. 10K Photoluminescence shows that if some of the main Cl related compensation processes are similar in poly-and mono-crystalline materials, specific mechanisms are evidenced in polycrystalline layers involving complexes between chlorine atoms and extrinsic point defects in the vicinity of structural defects (e.g. extended defects). Using low temperature Cathodoluminescence imaging, it is also demonstrated that structural defects can be efficiently passivated by chlorine atoms, leading to improved electro-optical properties. Finally, using cross-section photoluminescence on thick layers, we correlate the evolution of the defect levels to that of the structural properties along the growth axis.

Effect of SiO2 and SiNx Passivation on CdTe based Solar Cells

“…al. [7] investigated the effect of polycrystalline chlorine doped CdTe layer. The chlorine atoms appear to compensate unintentional impurities and give rise to levels within the bandgap.…”