Saturated Low-Temperature Conductivity in Ultrafast Semiconductor Nanocomposites

TL;DR

This study investigates low-temperature electrical conduction in InGaAs:ErAs nanocomposites, revealing a transition from thermal activation to Anderson localization, with finite metallic conductivity observed at very low temperatures, explained by scaling theory.

Contribution

It provides new insights into the conduction mechanisms of ultrafast semiconductor nanocomposites at low temperatures, highlighting the transition to metallic behavior.

Findings

Conduction mechanisms progress from thermal activation to Anderson localization as temperature decreases.

Finite metallic conductivity persists at low temperatures, contrary to typical insulating behavior.

The observed conduction behavior aligns with Abrahams scaling theory.

Abstract

This article presents studies on low-field electrical conduction in the range 4-to-300 K for a ultrafast material: InGaAs:ErAs grown by molecular beam epitaxy. The unique properties include nano-scale ErAs crystallines in host semiconductor, a deep Fermi level, and picosecond ultrafast photocarrier recombination. As the temperature drops, the conduction mechanisms are in the sequence of thermal activation, nearest-neighbor hopping, variable-range hopping, and Anderson localization. In the low-temperature limit, finite-conductivity metallic behavior, not insulating, was observed. This unusual conduction behavior is explained with the Abrahams scaling theory.