Impact of defect occupation on conduction in amorphous Ge2Sb2Te5.
Impact of defect occupation on conduction in amorphous Ge2Sb2Te5.
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DOI：
10.1038/srep31699
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发表时间：
2016-08-16
影响因子：
4.6
通讯作者：
Salinga M
中科院分区：
文献类型：
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作者：
Kaes M;Salinga M
利用相变存储器（PRAM）电阻的存储概念近年来已经成熟。试图对主导PRAM器件电阻的相变材料的非晶态传导进行建模，通常会以“陷阱状态之间的距离”的形式调用与活性材料的电子态密度（DoS）的联系。在这里，我们指出s取决于缺陷的占据，因此取决于温度。为了验证这一点，我们数值研究了温度和光照变化如何影响Ge2Sb2Te5在do中的占据。采用基于Poole-Frenkel效应的电荷输运模型，我们将这些变化与非晶Ge2Sb2Te5横向器件的场和温度相关的电流-电压特性联系起来，在黑暗和照明下测量。与我们的计算一致，我们发现s具有明显的温度依赖性。由于器件电流指数依赖于s的值，因此考虑其温度依赖性对器件建模具有深远的影响。
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 Ge2Sb2Te5 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 Ge2Sb2Te5, 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.