Transport Properties and Device Prospects of Ultrathin Black Phosphorus on Hexagonal Boron Nitride
Transport Properties and Device Prospects of Ultrathin Black Phosphorus on Hexagonal Boron Nitride
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DOI：
10.1109/ted.2017.2759124
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发表时间：
2017-12-01
影响因子：
3.1
通讯作者：
Wang, Han
中科院分区：
文献类型：
--
作者：
Esqueda, Ivan S.;Tian, He;Wang, Han
黑磷（BP）作为一种有前途的层状材料重新出现，在未来的纳米电子应用中具有巨大的潜力。最近的几项研究表明，当使用六方氮化硼 (hBN) 与 SiO2 基板绝缘（或完全封装时），BP 通道的传输特性得到改善。这种改进通常使用基于电导率和载流子密度之间的经验关系的迁移率提取来表征。然而，这并不能提供对输运机制的深入了解，也不能在分析中考虑内在（例如带隙和有效质量）和外在（例如陷阱密度/分布和肖特基势垒高度）特性的差异。在这里，我们提出了一种基于兰道尔理论的具有低维沟道材料的肖特基势垒 MOSFET 的建模方法。为了分析六方氮化硼绝缘 BP 通道中传输性能的改善，我们制造并测量了带有和不带有六方氮化硼绝缘层的 BP 肖特基势垒 MOSFET。我们的分析表明，与直接在 SiO2 上具有 BP 的器件相比，具有底层 hBN 层的 BP 器件的低场有效沟道迁移率提高了 80%，并且（能量平均）散射平均自由程增加了 5 倍以上。
Black phosphorus (BP) has re-emerged as a promising layered material with significant potential for future nanoelectronic applications. Several recent studies have demonstrated an improvement in the transport properties of BP channels when insulated from SiO2 substrates using hexagonal boron nitride (hBN) (or when fully encapsulated). This improvement is typically characterized using extractions of mobility based on the empirical relationship between conductivity and carrier density. However, this does not provide insight into the transport mechanisms, nor it allows accounting for differences in intrinsic (e. g., bandgap and effective mass) and extrinsic (e. g., trap density/distribution and Schottky barrier heights) properties in the analysis. Here, we present a modeling approach for Schottky-barrier MOSFETs with low-dimensional channel materials based on the Landauer theory. To analyze transport improvement in hBN-insulated BP channels we fabricate and measure BP Schottky-barrier-MOSFETs with and without the hBN insulating layer. Our analysis demonstrates similar to 80% improvement in low-field effective channel mobility and an (energy averaged) scatteringmean free path that is> 5 times larger forBPdeviceswith an underlyinghBN layer compared to devices with BP directly on SiO2.