Molecular electronics at Metal / Semiconductor Junctions Si inversion by Sub-nm Molecular Films

TL;DR

This study reveals that electron transport at metal/semiconductor junctions with ultra-thin molecular films is dominated by minority carriers and recombination processes, challenging previous thermionic emission assumptions and enabling new interface control strategies.

Contribution

It demonstrates that electron transport is independent of alkyl chain length and dominated by minority carriers, providing new insights into molecular electronics at semiconductor interfaces.

Findings

Transport is chain-length independent from 1 to 18 carbons.

Transport is dominated by minority carriers and recombination.

Direct binding of molecules offers new interface control options.

Abstract

Electronic transport across n-Si-alkyl monolayer/Hg junctions is, at reverse and low forward bias, independent of alkyl chain-length from 18 down to 1 or 2 carbons! This and further recent results indicate that electron transport is minority, rather than majority carrier-dominated, occurs via generation and recombination, rather than (the earlier assumed) thermionic emission and, as such is rather insensitive to interface properties. The (m)ethyl results show that binding organic molecules directly to semiconductors provides semiconductor/metal interface control options, not accessible otherwise.