Role of Ion Milling Angle in Determining Conducting and Insulating States on SrTiO3 Surfaces

TL;DR

This paper explores how ion milling angle influences the surface conductivity of SrTiO3, revealing that larger angles induce a high-mobility conducting surface, which is crucial for device fabrication.

Contribution

It demonstrates the critical role of ion milling angle in controlling the insulating or conducting states of SrTiO3 surfaces, providing guidelines for surface engineering.

Findings

Ion milling at angles below 10° preserves insulation.

Angles above 10° induce high-mobility conduction.

Transition linked to milling penetration depth exceeding lattice constant.

Abstract

SrTiO3 (STO), a promising wide-bandgap semiconductor for high-k capacitors and photocatalysis, requires precise surface control for device fabrication. This study investigates the impact of ion milling on STO's surface conductivity. We find that ion milling at incident angles below 10 degree preserves the insulating state, while ion milling at larger angles induces a conducting surface with high electron mobility (5000-11000 cm2/Vs). This transition is attributed to the milling penetration depth exceeding the STO lattice constant (3.905 {\AA}). Our results provide valuable insights for optimizing STO-based device fabrication, enabling precise control over surface properties while maintaining desired insulating characteristics.