發(fā)布時(shí)間：2018-02-13 21:39

  本文關(guān)鍵詞： III-V族半導(dǎo)體 GaN/AlN超晶格 第一性原理 帶隙 缺陷　出處：《北京工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：GaN、AlN以及Ga N/AlN的異質(zhì)結(jié)構(gòu)作為第三代半導(dǎo)體在紫外發(fā)光器件以及在高功率、高頻、高溫等電子器件等方面具有廣泛的應(yīng)用。其中GaN/AlN半導(dǎo)體超晶格作為一種人工材料,可以通過(guò)調(diào)節(jié)勢(shì)壘層的厚度比、控制摻雜等方式控制材料性質(zhì),引起了人們的廣泛關(guān)注。本文基于密度泛函的第一性原理計(jì)算,通過(guò)研究纖鋅礦與閃鋅礦結(jié)構(gòu)的GaN/AlN超晶格體系在不同勢(shì)壘層的厚度比和摻雜離子情況下,系統(tǒng)探究結(jié)構(gòu)調(diào)控、結(jié)構(gòu)缺陷以及摻雜對(duì)電學(xué)性質(zhì)的影響,這將為新型超晶格器件設(shè)計(jì)與研發(fā)提供理論指導(dǎo),主要研究結(jié)果如下:首先,主要討論本征半導(dǎo)體超晶格結(jié)構(gòu)的帶隙變化。結(jié)果表明:在保持超晶格總層數(shù)不變的情況下,無(wú)論是對(duì)纖鋅礦或是閃鋅礦結(jié)構(gòu)體系,隨著勢(shì)壘層的加厚其能帶間隙均呈現(xiàn)先減小后增大的拋物線的趨勢(shì)。當(dāng)超晶格勢(shì)壘勢(shì)阱層的厚度相等時(shí),其帶隙達(dá)到最小值。其次,主要研究空位缺陷對(duì)超晶格能帶結(jié)構(gòu)的影響。結(jié)果表明:氮空位為GaN/AlN半導(dǎo)體超晶格的主要缺陷。對(duì)于纖鋅礦結(jié)構(gòu),陽(yáng)離子缺陷(比如Al或者Ga空位)易在界面B(GaN區(qū)域的最后一層Ga層和AlN區(qū)域的第一層Al層之間的界面),而陰離子缺陷(N空位)易在勢(shì)阱層(GaN區(qū)域)內(nèi)形成。最后,主要研究摻雜Mg和Si離子對(duì)纖鋅礦和閃鋅礦兩種結(jié)構(gòu)的能帶結(jié)構(gòu)的影響。研究發(fā)現(xiàn),對(duì)于纖鋅礦和閃鋅礦體系,Si原子摻入結(jié)構(gòu)的形成能比Mg原子的形成能低,表明Si摻雜原子較易引入結(jié)構(gòu),并且雜質(zhì)易引入勢(shì)阱(GaN)區(qū)。同時(shí),發(fā)現(xiàn)閃鋅礦結(jié)構(gòu)較纖鋅礦結(jié)構(gòu)更易于摻雜。
[Abstract]:Gan / AlN and GaN/AlN heterostructures are widely used as third generation semiconductors in ultraviolet luminescent devices and electronic devices such as high power, high frequency, high temperature, etc. Among them, GaN/AlN semiconductor superlattices are used as artificial materials. The properties of materials can be controlled by adjusting the thickness ratio of barrier layer and controlling doping. The effects of structure regulation, structural defects and doping on electrical properties of wurtzite / sphalerite GaN/AlN superlattice system were investigated systematically under different barrier layer thickness ratios and doping ions. This will provide theoretical guidance for the design and development of new superlattice devices. The main results are as follows: firstly, the band gap changes of intrinsic semiconductor superlattice structures are discussed. For wurtzite and sphalerite structures, the band gap decreases first and then increases with the thickening of barrier layer. When the thickness of the barrier well layer is equal, the band gap reaches the minimum. The effect of vacancy defects on the band structure of superlattices is studied. The results show that nitrogen vacancies are the main defects of GaN/AlN semiconductor superlattices. Cationic defects (such as Al or Ga vacancies) are easily formed at the interface between the last layer of Ga and the first layer of Al in the AlN region, while the anionic defects are easily formed in the potential well layer (gan). The effect of doping mg and Si ions on the energy band structure of wurtzite and sphalerite is studied. It is found that the formation energy of Si doped structure in wurtzite and sphalerite system is lower than that of mg atom. The results show that Si doped atoms are easy to be introduced into the structure and impurities to the potential well / gan region. It is also found that the sphalerite structure is more easily doped than wurtzite structure.
【學(xué)位授予單位】：北京工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN304.2

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本文編號(hào)：1509160