共溅法制备Mn掺杂GaN薄膜和纳米结构的研究

发布时间：2018-05-23 07:22

本文选题：GaN + 纳米结构　；参考：《山东师范大学》2010年硕士论文

【摘要】： 半导体产业发展经历了第一代半导体材料Si、Ge等,第二代半导体材料GaAs、GaP等以及第三代半导体材料SiC、ZnSe、GaN等。以氮化镓(GaN)为代表第三代半导体材料与前两代相比,具有高热导率、耐高温、抗辐射、化学稳定性好、高强度和高硬度、宽直接带系,内、外量子效率高等特性,更适合于制作高温、高频及大功率电子器件及短波激光器,在微电子和光电子领域具有广阔的应用前景。由于一维GaN纳米材料具有许多新奇的物理特性而作为新颖的低维材料越来越多引起了人们的研究兴趣。随着GaN基器件的发展需求,为了更好地实现其光电子特性,适当的掺杂是非常有必要的。掺有Mn、Fe等过渡金属元素的Ⅲ—Ⅴ族稀磁半导体(DMS)材料,由于其具备半导体和磁性材料的综合特性,可望广泛应用于未来的磁(自旋)电子器件。掺Mn的氮化镓基稀磁半导体材料的居里温度超过室温,是能实现室温或更高温度下载流子诱导铁磁性的优选材料。于是在实现GaN一维纳米结构生长的基础上,进一步实现GaN纳米结构的Mn掺杂意义重大。本文采用共溅法制备Mn掺杂GaN纳米结构。用X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电镜(HRTEM)、傅里叶红外吸收谱(FTIR)、X射线光电子能谱(XPS)和光致发光谱(PL)等测试手段详细分析了Mn掺杂GaN纳米材料的结构、组分、形貌和光致发光特性。研究了不同的氨化温度、不同的氨化时间和不同氨气流量对GaN纳米结构的影响,初步提出并探讨了此方法合成GaN纳米结构的生长机制。所取得的主要研究结果如下: 1.用共溅射和氨化制备Mn掺杂GaN纳米结构利用磁控溅射法在Si衬底上溅射Mn/Ga_2O_3层状结构薄膜,然后对溅射的Mn/Ga_2O_3层状薄膜在氨气气氛下退火制备GaN纳米结构。通过改变退火时间、退火温度及氨气流量,研究其对合成的GaN纳米结构的影响。研究结果表明:不同的退火温度、退火时间和氨气流量对合成GaN纳米结构都有很大影响,合成的一维纳米结构为扁平条状六方纤锌矿结构的单晶Mn掺杂GaN。 2.GaN纳米结构的光学特性室温下,用波长为325 nm光激发样品表面,所得PL谱只包含二个主要的发光峰,分别对应位于388 nm和409 nm处。位于409 nm的很强的发光峰,与文献报道的GaN体材料的发光峰相比有较大的红移。说明Mn掺杂有效的调整了GaN纳米条的能带结构,减小了禁带宽度,改变了其在紫外光区的发光行为。388 nm处的发光峰可能是由于导带或施主态到Mn受主间的跃迁引起的。 3.对GaN纳米结构生长机制的探索高温下氨气逐步分解成NH_2、NH、H_2、N_2等产物,固态Ga_2O_3与H_2反应生成中间产物气态的Ga_2O,在衬底处与体系中氨气发生催化反应得到GaN晶核,这些晶核在衬底合适的能量位置生长,成为下一个晶核生长的依托点,随着氨化过程的进行GaN晶核继续长成GaN微晶,当微晶的生长方向沿着相同的方向生长,就形成了单晶GaN纳米线、纳米线、纳米颗粒。同时氨化层状结构的Mn/Ga_2O_3薄膜,能使得在微晶生长过程中,会有更多的Mn离子进驻GaN晶体内部,实现了Mn的有效掺杂。更深刻的原因仍在进一步的研究之中。
[Abstract]:The development of semiconductor industry has experienced the first generation of semiconductor materials Si, Ge, second generation semiconductor materials GaAs, GaP, and third generation semiconductor materials SiC, ZnSe, GaN and so on. With gallium nitride (GaN) as the representative of the third generation semiconductor materials, compared with the first two generation, it has high thermal conductivity, high temperature resistance, radiation resistance, chemical stability, high strength and hardness, wide straight. The band system, internal and external quantum efficiency, is more suitable for the manufacture of high temperature, high frequency and high-power electronic devices and short wave lasers. It has a broad application prospect in the field of microelectronics and optoelectronics. Since one dimension GaN nanomaterials have many novel physical properties, more and more new low dimensional materials have been developed. With the development of GaN based devices, in order to better realize their optoelectronic properties, proper doping is necessary. The III - V diluted magnetic semiconductor (DMS) materials with transition metal elements such as Mn and Fe are expected to be widely used in future magnetic (spin) electrons because of their comprehensive properties of semiconductors and magnetic materials. The Curie temperature of the gallium nitride based dilute magnetic semiconductor doped with Mn exceeds the room temperature. It is the preferred material to induce ferromagnetism at room temperature or higher temperature downloader. Thus, on the basis of the realization of the growth of GaN one-dimensional nanostructures, the Mn doping of GaN nanostructures is further realized.
In this paper, Mn doped GaN nanostructures were prepared by CO sputtering. The structure, composition, morphology and Photoluminescence of Mn doped GaN nanomaterials were analyzed in detail by X ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Fourier infrared absorption spectroscopy (FTIR), X ray photoelectron spectroscopy (XPS) and photoluminescence (PL). The effect of different ammoniation temperature, different ammoniation time and different ammonia flow on the GaN nanostructure was studied. The growth mechanism of GaN nanostructure was preliminarily proposed and discussed. The main results obtained are as follows:
1. preparation of Mn doped GaN nanostructures by CO sputtering and ammoniation
Mn/Ga_2O_3 layered structure films were sputtered on Si substrate by magnetron sputtering, and then the GaN nanostructures were annealed in the ammonia atmosphere by the sputtering Mn/Ga_2O_3 layer. The effects of annealing time, annealing temperature and ammonia flow on the synthesized GaN nanostructures were investigated. The time of fire and the flow of ammonia have a great influence on the synthesis of GaN nanostructures. The synthesized one-dimensional nanostructure is the single crystal Mn doped GaN. with a flat strip of six square wurtzinc structure.
Optical properties of 2.GaN nanostructures
At room temperature, the sample surface was excited with a wavelength of 325 nm light, and the obtained PL spectrum contains only two main luminescence peaks, which correspond to 388 nm and 409 nm respectively. The strong luminescence peak at 409 nm has a larger red shift compared with the luminescence peak of the reported GaN body material. It shows that Mn doping effectively adjusts the band structure of GaN nanoscale strip, and reduces the band structure of GaN nanoscale strips. The forbidden band width has changed its luminescence behavior in the ultraviolet region. The luminescence peak at.388 nm may be due to the transition between the conduction band or donor state to the acceptor of Mn.
3. research on the growth mechanism of GaN nanostructures
The ammonia gas is gradually decomposed into NH_2, NH, H_2, N_2 and other products at high temperature. The solid Ga_2O_3 and H_2 react to produce the Ga_2O in the gaseous state of the intermediate product. The nucleation of the GaN crystal is obtained at the substrate with the ammonia in the system. These nuclei grow at the appropriate energy position of the substrate and become the basis for the growth of the next nucleation. With the ammoniation process, the GaN crystal is carried out. The nucleation continues to grow into GaN microcrystals. When the growth direction of microcrystals grows in the same direction, the single crystal GaN nanowires, nanowires and nanoparticles are formed. At the same time, the Mn/Ga_2O_3 film of ammoniated layered structure can make more Mn ions in the GaN crystal during the microcrystalline growth process, and the effective doping of Mn can be realized. More profound reasons are realized. Further research is still under way.
【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TB383.1

【参考文献】