Conduction Mechanism in Amorphous NbTe₄ Thin Film

Abstract

This study explores the conduction mechanism of NbTe₄, a novel phase-change material (PCM) for phase-change random access memory (PCRAM), and addresses the limitations of the widely used Ge₂Sb₂Te₅ (GST). Unlike traditional PCMs, NbTe₄ in its amorphous state demonstrates low resistance, which indicates semiconductor behavior. However, the Hall and Seebeck coefficient measurements reveal an intriguing anomaly—amorphous NbTe₄ displays N-type conduction with Hall voltage and P-type conduction in the positive Seebeck coefficient. This Hall effect anomaly, which is typically associated with highly resistive chalcogenide materials, raises questions about the conduction mechanism in amorphous NbTe₄. This study delves into the electrical transport properties of NbTe₄ and provides insights into the unique characteristics of this PCM.