Atomic layer epitaxy of CdTe and MnTe

Atomic deposition techniques are investigated for binary semiconductors of the telluride family, namely CdTe and MnTe. An original method for directly determining the CdTe atomic layer epitaxy (ALE) growth rate—in monolayers/cycle—is proposed, consisting in monitoring the reflection high-energy electron diffraction (RHEED) sublimation intensity oscillations of an ALE grown CdTe layer deposited on a MgTe buffer layer. The ALE CdTe autoregulated growth rate at 0.5 monolayer/cycle (in the substrate temperature domain between 260 and 290 °C) is accounted for on the basis of an atomic model which relies on the alternating c(2×2) Cd and (2×1) Te surface reconstructions during the ALE cycle. RHEED studies on MnTe atomic deposition, together with x-ray diffraction and transmission electron microscopy on ALE grown CdTe/MnTe superlattices reveal that all deposited Mn atoms are incorporated so that no autoregulated growth can be achieved. Furthermore, less than one or just one monolayer of Mn must be sent on the surface per ALE cycle to obtain well controlled superlattices with abrupt interfaces