Optimisation of processing conditions during CVD growth of 2D WS2 films from a chloride precursor
Optimisation of processing conditions during CVD growth of 2D WS2 films from a chloride precursor
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DOI：
10.1007/s10853-021-06708-1
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发表时间：
2022-01-03
影响因子：
4.5
通讯作者：
Bending, Simon J.
中科院分区：
文献类型：
--
作者：
Campbell, William R.;Reale, Francesco;Bending, Simon J.
单层二硫化钨（WS 2）是一种直接带隙半导体，具有广泛的光电应用前景。WS 2的大面积生长先前已经使用W（CO）（6）前体成功地实现，然而，这是易燃的，并且在分解时是一氧化碳（CO）的潜在来源。为了解决这个问题，我们已经开发了一种工艺，用于在商业冷壁CVD反应器中从六氯化钨（WCl 6）前体中生长单层WS 2。与W（CO）（6）相比，WCl 6毒性较小，反应性较低，因此更适合于2D层的大规模CVD生长。我们表明，生长后的硫化氢退火可以导致我们的薄膜的光学质量的显着改善，证实了光致发光（PL）和拉曼测量。优化的膜表现出PL激子发射峰的半峰全宽为51 +/- 2毫电子伏，与其他国家的最先进的方法。我们证明，我们的WS 2膜可以很容易地从蓝宝石生长衬底转移到Si/SiO2目标衬底，使用聚苯乙烯支撑层的质量没有可检测到的退化。我们的方法代表了一个有前途的一步，工业规模的制造的p-n结，光电探测器和晶体管的基础上单层WS 2。
Monolayer tungsten disulphide (WS2) is a direct band gap semiconductor which holds promise for a wide range of optoelectronic applications. The large-area growth of WS2 has previously been successfully achieved using a W(CO)(6) precursor, however, this is flammable and a potent source of carbon monoxide (CO) upon decomposition. To address this issue, we have developed a process for the wafer-scale growth of monolayer WS2 from a tungsten hexachloride (WCl6) precursor in a commercial cold-wall CVD reactor. In comparison to W(CO)(6), WCl6 is less toxic and less reactive and so lends itself better to the large-scale CVD growth of 2D layers. We demonstrate that a post-growth H2S anneal can lead to a dramatic improvement in the optical quality of our films as confirmed by photoluminescence (PL) and Raman measurements. Optimised films exhibit PL exciton emission peaks with full width at half maximum of 51 +/- 2 meV, comparable to other state-of-the-art methods. We demonstrate that our WS2 films can be readily transferred from the sapphire growth substrate to a Si/SiO2 target substrate with no detectable degradation in quality using a polystyrene support layer. Our approach represents a promising step towards the industrial-scale fabrication of p-n junctions, photodetectors and transistors based on monolayer WS2.