Macroscopic Versus Microscopic Schottky Barrier Determination at (Au/Pt)/Ge(100): Interfacial Local Modulation

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Schottky barrier height (SBH) is critical for metal-semiconductor junction performance.
• Germanium (Ge) is a key material for next-generation electronic devices.
• Understanding interface properties is crucial for device miniaturization.

Purpose of the Study:

• To investigate the Schottky barrier height (SBH) at metal/Ge(100) junctions.
• To compare macroscopic and nanoscopic measurements of SBH.
• To elucidate the atomic origins of observed barrier variations.

Main Methods:

• Macroscopic current-voltage (I-V) measurements at room temperature.
• Nanoscopic ballistic electron emission spectroscopy (BEES) at 80 K.
• Ab initio theoretical modeling of BEES spectra.

Main Results:

• Macroscopic I-V measurements indicated a single SBH of 0.61-0.63 eV.
• Nanoscopic BEES revealed two distinct SBHs (0.61-0.64 eV and 0.70-0.74 eV).
• Macroscopic SBH correlated with the lower nanoscopic barrier.
• Two atomic registries at the metal/Ge(100) interface were identified as the cause of dual barriers.

Conclusions:

• Macroscopic measurements average out nanoscale variations in SBH.
• The coexistence of two SBHs is attributed to different atomic arrangements at the interface.
• This finding is significant for the design of advanced, miniaturized germanium-based electronic devices.