The determination of the x value in doped Hg1−xCdxTe by transmission spectra

Variable-temperature transmission/absorption spectra are measured on As-doped Hg1−xCdxTe grown by molecular beam epitaxy. The nonlinear temperature-dependent shift of the absorption edge is also observed, which is similar to our previous report on VHg (unintentionally)-doped HgCdTe. By referring to the empirical formulas of Eg(x, T), the x value of the epilayer is calculated and its inconsistency between the extreme temperatures (e.g. 10 and 300 K) is discussed. The results confirm the assumption of the effect of shallow levels on the shift of the absorption edge, and suggest that the x value (or Eg) in intrinsic/extrinsic-doped HgCdTe should be determined by referring to as low a temperature as possible (e.g. 10 K), and not the commonly used temperatures of 77 or 300 K, when the transmission spectrum should be employed. This can give brief guidelines for fabricating HgCdTe-related devices. (condensed matter: electronic structure, electrical, magnetic, and optical properties)