Crystallographically Controlled Synthesis of SnSe Nanowires: Potential in Resistive Memory Devices

Abstract

Here the controlled growth of SnSe nanowires by a liquid injection chemical vapor deposition (CVD) method employing a distorted octahedral [SnCl4{nBuSe(CH2)3SenBu}] single-source diselenoether precursor is reported. CVD with this single-source precursor allows morphological and compositional control of the SnSex nanostructures formed, including the transformation of SnSe2 nanoflakes into SnSe nanowires and again to SnSe nanoflakes with increasing growth temperature. Significantly, highly crystalline SnSe nanowires with an orthorhombic Pnma 62 crystal structure can be controllably synthesized in two growth directions, either <011> or <100>. The ability to tune the growth direction of SnSe will have important implications for devices constructed using these nanocrystals. The SnSe nanowires with a <011> growth direction display a reversible polarity-dependent memory switching ability, not previously reported for nanoscale SnSe. A resistive switching on/off ratio of 103 without the use of a current compliance limit is seen, illustrating the potential use of SnSe nanowires for low-power nonvolatile memory applications.