Open AccessImpact of defect occupation on conduction in amorphous Ge2Sb2Te5
Author(s) -
Matthias Kaes,
Martin Salinga
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep31699
Subject(s) - amorphous solid , phase change memory , condensed matter physics , materials science , thermal conduction , poole–frenkel effect , phase (matter) , optoelectronics , engineering physics , phase change , physics , chemistry , composite material , organic chemistry , quantum mechanics
Storage concepts employing the resistance of phase-change memory (PRAM) have matured in recent years. Attempts to model the conduction in the amorphous state of phase-change materials dominating the resistance of PRAM devices commonly invoke a connection to the electronic density-of-states (DoS) of the active material in form of a “distance between trap states s ”. Here, we point out that s depends on the occupation of defects and hence on temperature. To verify this, we numerically study how the occupation in the DoS of Ge 2 Sb 2 Te 5 is affected by changes of temperature and illumination. Employing a charge-transport model based on the Poole-Frenkel effect, we correlate these changes to the field- and temperature-dependent current-voltage characteristics of lateral devices of amorphous Ge 2 Sb 2 Te 5 , measured in darkness and under illumination. In agreement with our calculations, we find a pronounced temperature-dependence of s . As the device-current depends exponentially on the value of s , accounting for its temperature-dependence has profound impact on device modeling.