有机源制备的氢化非晶碳膜的新颖发光行为

Blue and Green Light Emission from a-C∶H Film Prepared by Organic Source

利用有机碳源 (二甲苯 ) ,采用等离子体增强化学气相沉积 (PECVD)系统制备了一系列氢化非晶碳 (a C :H)薄膜样品 .与利用甲烷 (CH4)制备的a C :H不同 ,该样品的光致发光峰位于蓝绿光范围并且呈现多峰结构 ,而不是表现为一个较宽的单峰 .同时样品发光峰的特征随着制备过程中功率不同而变化 .认为 :a C :H薄膜中的芳香环结构的引入产生了新的发光中心 。

Recently, hydrogenated amorphous carbon (a C∶H) was widely studied because of their unique properties and potential application in various opto-electronic devices. Conventional (a C∶H) films was fabricated by using methane as source. In this paper, (a C∶H) films were prepared by using organic hydrocarbon source, xylene (C 8H 10 ), in plasma enhanced chemical vapor deposition (PECVD) system. Very strong luminescence was observed from xylene based (a C∶H) films in room temperature. In contrast to a single broad photoluminescence (PL) peak from methane-based a C:H films, new PL feature was observed from xylene based (a C∶H) films in blue-green light region. Under rf power of 10?W, the PL spectra of xylene-based a-C:H films only show a single peak, which is similar with the methane-based (a C∶H) films. When rf power was increased to 30?W, two distinct peaks which were located at 420nm and 485?nm, appeared in the PL spectra. In the photoluminescence excitation spectra, (a C∶H) film prepared under rf power of 30?W showed a obvious excitation peak at 350?nm, whereas there was only a weak shoulder for the film prepared under rf power of 10?W. The Fourier-Transition Infrared spectrum show a new vibration modes in the region of 1?400～1?600?cm -1 in (a C∶H) films, which was believed to related to the sp 3 C=C bonds in aromatic structures. It was concluded that the aromatic structures can be enhanced in xylene-based (a C∶H) films deposited at high rf power, which may result in the existence of luminescence centers in the carbon films and induce the appearance of a new PL peak.