Co，Cu共掺杂ZnO薄膜的结构及发光特性

Structure and Optical Properties of (Co,Cu)-codoped ZnO Thin Films

采用电子束蒸发沉积成膜工艺在单晶Si(111)衬底上制备出Co,Cu共掺杂的Zn0.85-xCo0.15CuxO(x=0,0.04,0.06)多晶膜。采用X射线衍射(XRD)研究了Co、Cu掺杂对其微结构的影响;室温下测量了Zn0.85-xCo0.15CuxO薄膜的光致发光谱,发现随着Cu掺杂量的增加,样品发光增强,当Cu掺杂x=0.06时,Zn0.85-xCo0.15CuxO薄膜的PL谱中出现了较强的双峰蓝光发射;分析了掺杂含量对其发光性能的影响,并对样品的发光机制进行了探讨,并推断出蓝光峰来源于电子由导带底到锌空位(VZn)能级的跃迁及锌填隙(Zni)能级到价带顶的跃迁。

Over the past few years, wide and direct band gap semiconductors have been intensively studied for their application as blue and ultraviolet light emitters. As a wide gap semiconductor, ZnO has a wide band gap of 3. 37 eV and a large binding energy of 60 meV. Therefore, ZnO is considered as one of the most pro-mising candidates for short wavelength optoelectronics devices, and it is very important to conduct further studies of the properties of ZnO thin films. （ Co, Cu） -codoped ZnO thin films, Zn0.85-xCo0.15CuxO （x = 0,0.04,0.06 ） thin films were deposited on silicon（ 111 ） substrates by e-beam evaporation. The structure of Zn0.as_,Co0.15 Cu, O thin films were investigated using X-ray diffractometer （XRD）. Photoluminescent （PL） spectra were measured with Xe lamp excitation light source at room temperature, the excited wavelength was 325 nm. The photoluminescence spectrum reveals that with the increase of doping content of Cu, the emission intensity of Zn0.85-xCo0.15CuxO thin films was enhanced. Moreover, with x = 0.06, strong blue double emission peaks were got at 449 nm and at 477 nm for the Zn0.85-xCo0.15CuxO thin films. The luminescence mechanism was also discussed in this paper, The experiments prove that the blue emission is due to transition of electrons from the bottom of the conductor band to zinc vacancy VZn or interstitial zinc Zni to the top of valence band.