本文關(guān)鍵詞： 鐵電極化 鈮酸鋰 Sn Se薄膜 光電調(diào)控 脈沖激光沉積　出處：《哈爾濱工業(yè)大學》2015年碩士論文　論文類型：學位論文

【摘要】：Sn Se作為一種p型的窄禁帶半導體材料,其體材料的直接帶隙為1.3 e V,可吸收大部分波段的太陽光。作為IV-VI族化合物的一員,除了具有本族化合物常見的優(yōu)異性質(zhì)外還具有其它特殊的性質(zhì):層狀結(jié)構(gòu),具有各向異性,優(yōu)異的光電和熱電性質(zhì)等。針對元器件的低維化,集成化的需求,材料的薄膜化已成為重要發(fā)展趨勢。在薄膜化的基礎(chǔ)上,將鐵電材料與半導體薄膜結(jié)合,利用鐵電材料的極化性質(zhì)對半導體的能帶結(jié)構(gòu)和傳輸性質(zhì)進行調(diào)控,實現(xiàn)無源的介電器件和有源的半導體器件的結(jié)合也成為重要的研究熱點之一。本文探索了利用PLD和旋涂技術(shù)進行Sn Se薄膜的制備,得到不同極化方向的光鐵電鈮酸鋰/光電半導體Sn Se薄膜異質(zhì)結(jié),利用鐵電材料不同方向的極化電場與外加光場耦合來調(diào)控薄膜的光電性質(zhì),得到一種雙色光電探測器件。本文制得了結(jié)晶質(zhì)量較好的純相Sn Se薄膜,PLD生長薄膜的速度為2nm/min。光場和極化電場耦合作用對Sn Se薄膜的光電性質(zhì)起到了較好的調(diào)控效果。首先在暗場條件下,不同極化方向的電導產(chǎn)生四倍值的差距。在極化場作用下,極化方向指向薄膜的樣品引入屏蔽電子,薄膜處于高阻態(tài);極化方向背向薄膜的樣品,薄膜中引入屏蔽空穴,處于低阻態(tài)。這一結(jié)論在旋涂薄膜中也得以驗證。特別地,在405 nm激光照射下,對于極化方向指向薄膜的樣品,極化場會使鈮酸鋰與Sn Se接觸處的界面電勢下降,由于接觸后鈮酸鋰的導帶位置低于Sn Se導帶位置,當鈮酸鋰發(fā)生光電子躍遷,光電子并不能向Sn Se導帶進行傳輸,而空穴可以在鈮酸鋰價帶位置向薄膜傳輸,會增加薄膜光電導;對于極化方向背向薄膜的樣品,會使界面兩側(cè)電勢能增加,鈮酸鋰能帶向上彎曲超過Sn Se能帶,而在發(fā)生光電效應(yīng)時,光電子可以向薄膜進行傳輸,降低p型薄膜的光電導。通過利用光、電場耦合調(diào)控n型Cd Se半導體薄膜的結(jié)果,第五章進一步驗證了調(diào)控模型。Cd Se在405 nm波長激光作用下出現(xiàn)了相反的調(diào)控現(xiàn)象,當極化方向指向薄膜,Cd Se的光電導相比632 nm照射下出現(xiàn)降低的現(xiàn)象,正是由于極化場使界面兩側(cè)的勢能降低,會有空穴向薄膜傳輸,而在另一極化方向的樣品中,極化場使界面兩側(cè)的電勢增加,鈮酸鋰的導帶高過Sn Se的能帶,會有光電子向薄膜傳輸,光電導并沒有降低反而會出現(xiàn)增加。
[Abstract]:As a p-type narrow band gap semiconductor material, Sn se has a direct band gap of 1. 3 EV and absorbs most of the solar light. It is a member of IV-VI family compounds. In addition to the common excellent properties of their own compounds, they also have other special properties: layered structure, anisotropy, excellent optoelectronic and thermoelectric properties, etc. The thinning of materials has become an important development trend. On the basis of thinning, ferroelectric materials are combined with semiconductor thin films to regulate the energy band structure and transport properties of semiconductors by using the polarization properties of ferroelectric materials. The combination of passive dielectric devices and active semiconductor devices has also become one of the important research hotspots. In this paper, the preparation of Sn se thin films by PLD and spin coating techniques has been explored. The photoferroelectric lithium niobate / photodiode Sn se thin films with different polarization directions are obtained. The optoelectronic properties of the films are controlled by the coupling of the polarized electric field in different directions of ferroelectric materials with the external light field. A two-color photodetector is obtained. In this paper, the growth rate of pure phase Sn se thin film grown by PLD is 2 nm / min. The coupling of optical field and polarization electric field has a good effect on the photoelectric properties of Sn se thin film. Effect. First of all in the dark field conditions, Under the action of polarization field, the polarization direction leads to the introduction of shielded electrons into the film, and the film is in a high resistance state. This conclusion is also verified in spin-coated films. In particular, the interfacial potential of lithium niobate contact with Sn se decreases when the polarization direction is directed to the film under 405 nm laser irradiation. Because the conduction band position of lithium niobate is lower than that of Sn se after contact, when photoelectron transition occurs in lithium niobate, the photoelectron can not be transported to Sn se conduction band, but the hole can transport to the thin film at the valence band position of lithium niobate. The photoconductivity of the film is increased, and the potential energy on both sides of the interface increases for the sample with the polarization direction backward, and the band of lithium niobate bends upwards over the Sn se band, and in the event of photoelectric effect, the photoelectron can be transported to the film. The photoconductivity of p-type thin films is reduced. By using light and electric field coupling to control n-type CD se semiconductor films, chapter 5th further verifies that the regulation model, CD se, has the opposite regulation phenomenon under the action of 405nm wavelength laser. When the polarization direction is directed to the film, the photoconductivity of CD se decreases compared with that of 632 nm irradiation. It is precisely because the polarization field makes the potential energy on both sides of the interface lower, there will be hole transmission to the film, while in the other polarization direction sample, The polarization field increases the electric potential at both sides of the interface, and the conduction band of lithium niobate is higher than that of Sn se, and there will be photoelectron transmission to the thin film. Instead of decreasing the photoconductivity, the photoconductivity will increase.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ134.32;TB383.2

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相關(guān)碩士學位論文 前1條

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本文編號：1552457