Lattice relaxation of dimer islands on Ge(001) during homoepitaxy by pulsed laser deposition

TL;DR

This paper investigates how dimer islands on Ge(001) relax during low-temperature pulsed laser deposition, revealing anisotropic surface stress relaxation and metastable stress domains affecting island distribution.

Contribution

It provides new insights into lattice relaxation mechanisms and stress domain formation during pulsed laser deposition of Ge(001).

Findings

Displaced x-ray diffraction peaks indicate anisotropic relaxation.

Multilevel islands retain stress relaxation features.

Island distribution favors monodisperded islands with anisotropic relaxation.

Abstract

In low-temperature pulsed growth two-dimensional islands form and coarsen into ~10 nm features. The islands produce well-defined displaced x-ray diffraction peaks due to relaxation of anisotropic surface stress of the (2x1) reconstruction with expansion and contraction present in orthogonal directions. The relaxation carries over into multilevel islands, suggesting that domains in subsequent layers form metastable stress domains. We infer that the island distribution differs from continuous deposition, enhancing the population of monodisperded islands exhibiting anisotropic relaxation.