MeV ion-induced strain at nanoisland-semiconductor surface and interfaces

TL;DR

This study investigates how MeV ion irradiation induces strain at the surfaces and interfaces of silicon substrates and silver nanoislands, revealing lattice contraction and the effects of nanoisland shadowing using TEM and X-ray diffraction.

Contribution

It provides new insights into ion-induced strain effects at nanoisland-semiconductor interfaces using combined TEM and X-ray diffraction techniques.

Findings

Ion irradiation causes silicon lattice contraction.

Nanoislands reduce strain beneath them due to shadowing.

High-resolution imaging reveals strain around amorphization zones.

Abstract

Strain at surfaces and interfaces play an important role in the optical and electronic properties of materials. MeV ion-induced strain determination in single crystal silicon substrates and in Ag (nanoisland)/Si(111) at surface and interfaces has been carried out using transmission electron microscopy (TEM) and surface-sensitive X-ray diffraction. Ag nanoislands are grown under various surface treatments using thermal evaporation in high vacuum conditions. Irradiation has been carried out with 1.5 MeV Au^{2+} ions at various fluences and impact angles. Selected area electron diffraction (SAED) and lattice imaging (using TEM) has been used to determine the strain at surface and interfaces. Preliminary results on the use of surface-sensitive asymmetric x-ray Bragg reflection method have been discussed. The TEM results directly indicate a contraction in the silicon lattice due to ion-induced effects. The nanoislands have shadowed the ion beam resulting in lesser strain beneath the island structures in silicon substrates. High-resolution lattice imaging has also been used to determine the strain in around amorphization zones caused by the ion irradiation.