超高真空和射频炉制备的Si面和C面4H-SiC上外延石墨烯的比较。

Comparison of epitaxial graphene on Si-face and C-face 4H SiC formed by ultrahigh vacuum and RF furnace production.

作者信息

Jernigan Glenn G, VanMil Brenda L, Tedesco Joseph L, Tischler Joseph G, Glaser Evan R, Davidson Anthony, Campbell Paul M, Gaskill D Kurt

机构信息

US Naval Research Laboratory, Electronics Science and Technology Division Code 6800, 4555 Overlook Avenue SW, Washington, DC 20375, USA.

出版信息

Nano Lett. 2009 Jul;9(7):2605-9. doi: 10.1021/nl900803z.

DOI:10.1021/nl900803z

PMID:19583281

Abstract

We present X-ray photoelectron spectroscopy, van der Pauw Hall mobilities, low-temperature far-infrared magneto transmission (FIR-MT), and atomic force microscopy (AFM) results from graphene films produced by radiative heating in an ultrahigh vacuum (UHV) chamber or produced by radio frequency (RF) furnace annealing in a high vacuum chemical vapor deposition system on Si- and C-face 4H SiC substrates at 1200-1600 degrees C. Although the vacuum level and heating methods are different, graphene films produced by the two methods are chemically similar with the RF furnace annealing typically producing thicker graphene films than UHV. We observe, however, that the formation of graphene on the two faces is different with the thicker graphene films on the C-face RF samples having higher mobility. The FIR-MT showed a 0(-1) --> 1(0) Landau level transition with a square root B dependence and a line width consistent with a Dirac fermion with a mobility >250,000 cm(2) x V(-1) x s(-1) at 4.2 K in a C-face RF sample having a Hall-effect carrier mobility of 425 cm(2) x V(-1) x s(-1) at 300 K. AFM shows that graphene grows continuously over the varying morphology of both Si and C-face substrates.

摘要

我们展示了通过在超高真空（UHV）腔室中辐射加热制备的石墨烯薄膜，以及在1200 - 1600摄氏度下，在Si面和C面4H SiC衬底上的高真空化学气相沉积系统中通过射频（RF）炉退火制备的石墨烯薄膜的X射线光电子能谱、范德堡霍尔迁移率、低温远红外磁传输（FIR - MT）和原子力显微镜（AFM）结果。尽管真空水平和加热方法不同，但这两种方法制备的石墨烯薄膜在化学性质上相似，通常RF炉退火制备的石墨烯薄膜比UHV制备的更厚。然而，我们观察到在两个面上石墨烯的形成有所不同，C面RF样品上较厚的石墨烯薄膜具有更高的迁移率。FIR - MT显示在一个C面RF样品中，在4.2 K时出现了0（-1） --> 1（0）的朗道能级跃迁，其具有平方根B依赖性和线宽，该样品在300 K时的霍尔效应载流子迁移率为425 cm² x V⁻¹ x s⁻¹，且迁移率>250,000 cm² x V⁻¹ x s⁻¹。AFM表明石墨烯在Si面和C面衬底的不同形貌上连续生长。