Growth method, composition, and defect structure dependence of mercury diffusion in CdxHg1–xTe
Mercury radiotracer diffusion results are presented, in the range 254 to 452°C, for bulk and epitaxial CdxHg1–xTe, and we believe this to be the first report for metalorganic vapor phase epitaxy (MOVPE) grown CdxHg1–xTe. For all growth types studied, with compositions of xCd=0.2±0.04, the variation of the lattice diffusion coefficient, DHg, with temperature, under saturated mercury partial pressure, obeyed the equation: DHg=3×10−3 exp(−1.2 eV/kT) cm2 s−1.It was found to have a strong composition dependence but was insensitive to changes of substrate material or crystal orientation. Autoradiography was used to show that mercury also exploited defect structure to diffuse rapidly from the surface. Dislocation diffusion analysis is used to model defect tails in MOVPE CdxHg1–xTe profiles.