Strain relaxation during the layer by layer growth of cubic CdSe onto ZnSe

TL;DR

This study investigates how the lattice parameter of CdSe thin films relaxes during layer-by-layer growth on ZnSe, revealing oscillations linked to island formation and plastic deformation after several monolayers.

Contribution

It provides detailed in situ RHEED analysis of lattice relaxation phenomena during CdSe growth on ZnSe, highlighting the effects of island formation and plastic deformation.

Findings

Lattice parameter oscillates during growth, with minima during Se steps.

Island formation influences lattice relaxation behavior.

Plastic deformation occurs after approximately 5 monolayers.

Abstract

A detailed reflection high-energy electron diffraction analysis shows relevant features of the lattice parameter relaxation of CdSe thin films grown in a layer-by-layer mode onto ZnSe. In situ investigations of different azimuths show a clear lattice parameter oscillation in the 110 azimuth. The lattice parameter has a minimum value ~similar to that of ZnSe! during Se exposure steps, and a higher and increasing lattice parameter during Cd exposure steps. The behavior is ascribed to the formation of CdSe islands during Cd exposure steps. The cumulative effect in CdSe exposure steps is considered to be a consequence of a decrease in the island size with the number of cycles. Actual plastic deformation does occur after 5 ML.