離子液體閘極調控硒化銦場效電晶體的傳輸行為

Transport behavior of Ionic-liquid-gated layered InSe Field Effect Devices

白唯良(Wei-Liang Pai)

指導教授 ： 王偉華

共同指導教授 ： 梁啟德(Chi-Te Liang)

國立臺灣大學/理學院/物理學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201800624

摘要

二維層狀半導體，例如過鍍金屬硫族化物(TMDs)、黑磷與硒化銦 (InSe)，在近幾年來被密集地研究著。在二維半導體材料當中，硒化銦，由於其具有很小的有效質量 (effective mass) 與很高的載子遷移率 (carrier mobility)，因此在電子元件應用上非常具有潛力。另一方面，純粹由陰陽離子構成的離子液體(ionic liquid)，能使場效電晶體 (field-effect transistor) 的通道有效地達到高載子濃度。由於我們實驗室過去缺乏操作離子液體的技術，在製作與量測離子液體調控的場效電晶體時，遇到許多技術上的困難。經過我們研發後，我們開發並優化了調控離子液體閘極 (ionic liquid gating) 的技術。透過這項技術，我們得以控制並量測由離子液體調控的硒化銦場效電晶體，並研究其電性傳輸性質。相較於矽背閘極 (Si-back gate) 的硒化銦場效電晶體，我們觀察到離子液體對於硒化銦場效電晶體的電性傳輸效能的提升，離子液體閘極調控的硒化銦場效電晶體在200 K展現了超過1000 cm2/Vs的載子遷移率。在半導體與金屬的界面所形成的蕭特基位障 (Schottky barrier)可以透過離子液體閘極來調控，並且其值可以達到很低的33 meV。此外，我們還觀察到由於離子液體的相變，隨著溫度的變化的電性傳輸性質有了異常的趨勢，對於研究離子液體閘極調控的二維場效電晶體，這項發現提供了相關研究的另一方向。

關鍵字

硒化銦 ； 場效電晶體 ； 載子遷移率 ； 離子液體 ； 相變

並列摘要

Two-dimensional (2D) layered semiconductors, such as transition metal dichalcogenides (TMDs), black phosphorus and indium selenide (InSe), have been intensively studied during these years. Among the 2D semiconducting materials, InSe exhibits great potential for electronic applications because of its small effective mass and high carrier mobility. On the other hand, ionic liquid (IL), composed of anions and cations, is an efficient gating technique to achieve high carrier concentration in the semiconducting channel of the field effect transistors (FETs). Due to lack of experience to operate IL gating in our lab, we encountered several technical issues regarding device fabrication and electronic properties measurement. After spending some efforts, we developed and optimized the IL gating technique, which allows us to measure IL-gated InSe FETs with experimental control. We observed enhanced transport properties of IL-gated InSe FETs, as compared with the Si-back-gated InSe FETs. The IL-gated InSe FETs exhibits a high field effect mobility of ~1000 cm2/Vs at 200 K. For contact behavior, the Schottky barrier height can be modulated by IL gate and a small barrier height of 33 meV is achieved. Moreover, anomalous temperature dependent transport behavior enabled by the phase transition of IL is observed, which offers an alternative approach to control IL-gated 2D-semiconductor-based FETs.

並列關鍵字

InSe ； field-effect transistor ； mobility ； ionic liquid ； phase transition

參考文獻

[1] Gordon E., Moore, Cramming more components onto integrated circuits. Electronics, pp. 114–117, April 19, 1965.

[2] K. S. Novoselov, A. K. Geim1, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos,

I. V. Grigorieva1, and A. A. Firsov, Electric Field Effect in Atomically Thin Carbon Films. Science 22 Oct 2004 : 666-669.

[3] Kin Fai Mak, Changgu Lee, James Hone, Jie Shan, and Tony F. Heinz, Atomically thin MoS2: a new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010)

[4] B. Radisavljevic, A. Radenovic, J. Brivio, V. Giacometti, and A. Kis, Single-layer MoS2 transistors. Nature Nanotechnol. 6, 147-150 (2011)