Reflection mass spectrometry studies on UHV ALE of Cd1−xZnxTe (0≤x≤1) compounds

Simultaneous reflection mass spectrometry (REMS) and reflection high energy electron diffraction (RHEED) measurements of the surface kinetic and structural parameters, respectively, governing the UHV ALE growth of ZnTe and CdZnTe films are reported. Two sets of experiments have been performed. In the first one we have deposited several ZnTe ALE layers with different Zn/Te flux ratios, timing cycles and growth temperatures. The REMS signals for Zn+ cations during the deposition and `deadʹ times of the ALE cycle were measured; RHEED patterns were also recorded to control the smoothness of the epilayer. In the second part of our experiments a set of CdZnTe layers was grown by ALE. During the growth, the REMS signals were measured for both Zn+ and Cd+ cations. An interesting phenomenon is observed in the REMS Zn+ signal behavior during the ALE growth of ZnTe. In certain growth conditions, the REMS Zn+ signal increases in the presence of the Te2 molecules on the surface of the growing layer, probably due to partial reevaporation of the first chemisorbed layer of Zn. Similar behavior of the REMS Zn+ signal is observed for ALE growth of Cd0.5Zn0.5Te layer. However, in this case no changes in the Cd+ signal can be seen when the Te cell is opened.