Atomically Resolved Electron Reflectivity at a Metal/Semiconductor Interface

TL;DR

Researchers created an ultra-smooth metal/semiconductor interface and used atomic-level imaging to detect electronic changes at the boundary.

Contribution

A novel non-destructive method for detecting buried interfacial electronic states using atomic-resolution STM.

Findings

An atomically flat Al/Ge interface was fabricated using MBE.

STM revealed a 22% lateral variation in electron reflectivity over 2 nm at the interface.

The reflectivity changes are attributed to local electronic states at the interface.

Abstract

An atomically flat interface is achieved between face‐centered cubic Al and diamond lattice Ge via molecular beam epitaxy (MBE). Based on the measurements of scanning tunneling microscopy (STM), an atomically resolved lateral periodic change of the electron reflectivity at the Al/Ge interface is demonstrated. The relative variation of electron reflectivity is up to ≈22% in a lateral 2 nm. It is speculated that the change of reflectivity results from the local electronic states at the Al/Ge interface. This phenomenon provides an atomically non‐destructive method for detecting the buried interfacial states in hetero‐structures by STM.

An atomically flat interface is achieved in the incoherent Al/Ge heterostructure using molecular beam epitaxy (MBE). Scanning tunneling microscopy (STM) reveals a laterally periodic modulation of electron reflectivity with atomic resolution at the commensurate Al/Ge interfacial lattice, originating from the local electronic states. This phenomenon provides a method for detecting buried interfacial states in heterostructures.

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