【作者】 徐小燕；

【导师】 杨德仁； 马向阳；

【作者基本信息】 浙江大学 ， 材料科学与工程， 2012， 硕士

【摘要】 ZnO由于大的禁带宽度(3.37eV)和室温下高的激子束缚能(60meV)而被认为做为紫外发光器件最有潜力的材料之一。CdO禁带宽度为2.3eV,它与ZnO形成的CdZnO合金半导体则是应用于可见发光的潜在材料。本文研究了硅基Zn0(CdZnO)薄膜的发光性质；在此基础上,制备了电致发光器件,对器件的电致发光性能进行了研究。本文得到的主要结果如下：1.利用直流反应溅射法在Si衬底制备ZnO薄膜,研究了ZnO薄膜经不同条件的快速热处理后的光致发光。结果表明：经Ar气氛下800℃快速热处理后的ZnO薄膜比在O2气氛下800℃快速热处理的ZnO薄膜显示出更强的近带边发光。然而,后者再经过Ar气氛下低温60℃热处理后,其近带边发光强度则可与前者的相比拟。分析认为,ZnO薄膜经氧气氛下快速热处理后在其表面存在吸附的氧离子,它们对近带边光致发光不利。2.以直流反应溅射法制备的ZnO薄膜做为半导体层,以射频反应溅射法制备的SiO2做为绝缘层,在重掺N型硅衬底上制备基于ZnO的金属-绝缘体-半导体(MIS)结构的发光器件。当SiO2厚度约为12nm时,器件在一定的正偏压下产生随机激射,而当SiO2厚度小于～9 nm时,器件仅产生自发辐射的电致发光。因此,只有当SiO2厚度足够厚时,高浓度的载流子才会限域在ZnO/Si02界面附近,从而为随机激射创造条件。3.利用射频反应溅射制备CdZnO薄膜,研究热处理条件对薄膜晶体结构、表面形貌及光致发光的影响。研究发现：随着快速热处理温度的提高与时间的延长,CdZnO薄膜表面由于Cd的挥发加剧而形成更多的空洞,薄膜的近带边光致发光则发生蓝移。以CdZnO/Si02(MgO)/P+-Si为结构的器件在足够大的正向偏压下产生源于CdZnO带边辐射的电致发光。更多还原

【Abstract】 With a wide direct band gap of 3.37 eV and large exaction binding energy of 60 meV at room temperature, ZnO is considered as one of the most promising materials for ultraviolet (UV) optoelectronics. The band gap of CdO is 2.3 eV. ZnO is expected to be the photolectric material in visible region when alloyed with CdO. In this paper the photoluminescence of silicon-based ZnO (CdZnO) films has been studied. Moreover, light-emitting devices were prepared and the electroluminescent of them has been investigated. The primary achievements are as follows.1. ZnO films were deposited on the silicon subtract by direct current sputtering. The effect of RTA conditions on photoluminescence has been investigated. It is found that the ZnO film received the RTA at 800℃under Ar ambient shows much stronger PL than that received the RTA at 800℃under O2 ambient. With the post-RTA at 60℃under Ar ambient, the ZnO film received the RTA at 800℃under O2 ambient exhibits ultraviolet (UV) PL as intense as that of the ZnO film received the RTA at 800℃under Ar ambient. It is supposed that a certain amount of negatively charged oxygen species exist on the surface of the ZnO film received the RTA under O2 ambient, leading to a build-in electric field. This in turn reduces the recombination probability of photo-generated electrons and holes, resulting in the suppressed NBE PL.2. With the ZnO and SiO2 acted as the semiconductor and insulator, the ZnO-MIS device was prepared on the n+-Si substrate by sputtering method. Under forward bias, the ZnO-MIS structure demonstrates random laser when the thickness of SiO2 is at-12 nm. With SiO2 thickness decreased to-9 nm, there is only spontaneous emission from ZnO-MIS structure. Only when the SiO2 is thick enough the random laser can be produced under forward bias with high concentration carriers accumulated in the Zn0/SiO2 interface.3. The CdZnO films were deposited by radio frequency sputtering and the effect of RTA conditions on crystal structure, surface morphology and photoluminescence has been investigated. It is shown that with the increase of RTA temperature and RTA time, more voids are formed in the films due to the volatilization of Cd. In the meantime, the PL peak of CdZnO shows blue-shift. The CdZnO/SiO2 (MgO)/P+-Si structure was fabricated and the device exhibits the near-band-edge (NBE) emission from CdZnO.更多还原