From Trimers to Chains: Growth and Defect Dynamics in Anisotropic Tellurium Films

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Tellurium (Te) thin films form one-dimensional (1D) helical atomic chains.
• These chains exhibit tunable semiconducting properties based on dimensionality.
• A triangular arrangement of three Te atoms, a trimer, is the fundamental structural motif.

Purpose of the Study:

• Investigate layer-dependent electronic structure changes in Te trimers.
• Characterize defects in Te thin films across different thicknesses.
• Explore the impact of surface treatments on the electronic properties of Te films.

Main Methods:

• Scanning tunneling microscopy (STM) for surface imaging and electronic structure analysis.
• Growth of Te thin films with varying thicknesses on Au(100).
• Atomic layer deposition (ALD) of amorphous Al2O3 for surface modification.

Main Results:

• Monolayer and bilayer Te films show trimer vacancy clusters.
• Thicker Te films exhibit 1D chains of missing row atoms or edge dislocations instead of isolated vacancies.
• These defects contribute to the intrinsic p-type semiconducting behavior.
• ALD of Al2O3 induces surface transfer doping, converting p-type to n-type characteristics.

Conclusions:

• The type and distribution of surface defects in tellurium thin films dictate their electronic properties.
• Surface engineering via ALD offers a pathway to control the conductivity type of tellurium films.
• Understanding defect-property relationships is crucial for tailoring tellurium-based electronic devices.