Temperature‐Dependent Electronic Transport in Non‐Bulk‐Resistance‐Variation Nitrogen‐Doped Cr2Ge2Te6 Phase‐Change Material. Issue 3 (22nd October 2020)

• Record Type: Journal Article
• Authors: Shuang, Yi; Hatayama, Shogo; Ando, Daisuke; Sutou, Yuji
• Is Part Of: Physica status solidi. Volume 15:Issue 3(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-22
• Subjects: Cr2Ge2Te6 -- electronic transport -- nitrogen‐doping -- phase‐change materials -- Schottky contact -- variable‐range hopping; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.202000415
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : The electronic transport mechanism of the nitrogen‐doped Cr2 Ge2 Te6 (NCrGT) phase‐change material (PCM) is studied, showing almost zero resistivity variation upon phase transition. A similar low‐temperature variable‐range hopping (VRH) behavior in both the amorphous and crystalline phases of the NCrGT PCM is observed by measuring the temperature‐dependent resistivity. At high temperatures above 300 K, the conduction mechanism in the amorphous NCrGT is thermally activated band conduction, while the carrier transport in the crystalline NCrGT is still driven by VRH. Moreover, Hall property measurements reveal a thermally activated carrier in the amorphous NCrGT and mobility‐driven hopping conduction in the crystalline NCrGT at a high temperature range from 300 to 400 K. The conduction mechanism difference between the amorphous and crystalline NCrGT/tungsten (W) contacts is further investigated by measuring the temperature‐dependent I – V characteristics. The conduction in the amorphous NCrGT/W contact is dominated by thermionic‐field emission, while the transport mechanism through the crystalline NCrGT/W interface is controlled by the defect‐assisted tunneling current. Such noticeable conduction mechanism variation results in a large contact resistance contrast in a memory cell. Abstract : The temperature‐dependent electrical properties of a nitrogen‐doped Cr2 Ge2 Te6 (NCrGT) phase‐change material (PCM) in its amorphous and crystalline phases are investigated. At the temperature range of 300–400 K, a different conduction mechanism can be obtained in these two phases even though a zero resistivity variation occurs upon phase transition from amorphous to crystalline phase.