Photoluminescence and Electrical Conductivity of As2S3〈Au〉 and As2S5〈Au〉 Glasses

Abstract

The 77-K photoluminescence spectra of ( As 2 S 3 ) 100x Au x and (As 2 S 5 ) 100x Au x ( 0 ≤ ı ≤ 0.04 ) semiconducting glasses are measured for the first time. At low doping levels, the spectra of the ( As 2 S 5 ) 100x Au x glasses are split into two components, one of which arises from the Au dopant. The temperature-dependent conductivity of the glasses shows two breaks at low Au concentrations and anomalous behavior in the range 300-360 K. Qualitative analysis of the conductivity data suggests that most of the impurity atoms have saturated valence bonds and form solid solutions with host atoms, changing the band gap of the material. A small fraction of the impurity atoms, those having unsaturated valence bonds, produce an electrically active level responsible for impurity conduction.

Structure‐Dependent Electrical Properties of Carbon Nanotube Fibers

“…At temperatures below 250 K, the conductivity increased with temperature, indicating a semiconductive nature. At temperatures higher than 250 K, the conductive behavior changed to metallic, but then switched back to semiconductive when temperatures were above 280 K. Such conductivity fluctuations were also observed in DNA-linked Au nanoparticle aggregates [32] and Au composites, [33] implying that Au nanoparticles play an important role in the conducting behavior of the fiber at higher temperatures but the conductance at lower temperatures is dominated by CNTs.…”