本文選題：超導(dǎo)單光子探測器　切入點：NbN薄膜　出處：《南京大學(xué)》2015年碩士論文

【摘要】：單光子探測技術(shù)既具有重要的科學(xué)意義也有廣泛的應(yīng)用領(lǐng)域,在量子秘鑰分發(fā)、量子計算、熒光探測、微弱光成像等方面均有重要作用。超導(dǎo)納米線單光子探測器基于超導(dǎo)納米線條中非平衡態(tài)的熱電子效應(yīng),具有速度快、探測范圍寬和暗記數(shù)低的優(yōu)點,通過光學(xué)諧振腔或光學(xué)波導(dǎo)結(jié)構(gòu),系統(tǒng)探測效率也可達(dá)到80%以上,是目前綜合性能最佳的單光子探測器,因此受到了學(xué)界關(guān)注。高質(zhì)量的超導(dǎo)薄膜是制備超導(dǎo)單光子探測器的基礎(chǔ)和關(guān)鍵。本文主要研究超薄的NbN薄膜和低能隙的NbSi薄膜的制備與表征,通過優(yōu)化工藝條件,在多種襯底上制備出高質(zhì)量的超薄NbN和NbSi薄膜。文中對兩套制備系統(tǒng)的結(jié)構(gòu)和操作方法都進(jìn)行了詳細(xì)介紹,并給出了兩種薄膜的詳細(xì)制備流程。我們使用臺階儀、能量色散X射線光譜儀(EDX)、X射線衍射儀(XRD)、原子力顯微鏡(AFM)和掃描電子顯微鏡(SEM)等手段系統(tǒng)表征了NbN和NbSi兩種薄膜的厚度、結(jié)構(gòu)、成分、表面形貌等性能；利用液氦杜瓦測量系統(tǒng)和綜合物性測量系統(tǒng)(PPMS)表征了NbN和NbSi薄膜的超導(dǎo)轉(zhuǎn)變溫度。樣品的實驗測量表明,制備在MgO襯底上4nmNbN薄膜的超導(dǎo)轉(zhuǎn)變溫度超過12.5K,在Si襯底上6nmNbN薄膜的超導(dǎo)轉(zhuǎn)變溫度超過7.4K,在Si-SiOx襯底上6nmNbN薄膜的超導(dǎo)轉(zhuǎn)變溫度超過7.38K。利用共濺射工藝技術(shù),通過調(diào)節(jié)濺射電壓、濺射氣壓、靶材與襯底的距離等實驗參數(shù)制備出NbSi薄膜,成分分析表明,薄膜成分含量為Nb占65%,Si占30%,超導(dǎo)轉(zhuǎn)變溫度也達(dá)到了3K,這些工作為開發(fā)紅外及遠(yuǎn)紅外波段的超導(dǎo)單光子探測器打下了良好基礎(chǔ)。利用測量方阻法估算薄膜厚度,為超薄薄膜厚度的工藝檢測提供了一個快捷方便的手段,并已應(yīng)用于超導(dǎo)納米線單光子探測器的制備中,獲得很好效果。
[Abstract]:Single photon detection technology has important scientific significance as well as a wide range of applications in quantum secret key distribution, quantum computing, fluorescence detection, The single photon detector of superconducting nanowires is based on the thermionic effect of the nonequilibrium state of superconducting nanowires, which has the advantages of high speed, wide detection range and low number of dark memories. Through the optical resonator or optical waveguide structure, the detection efficiency of the system can also reach more than 80%, so it is the best single photon detector with the best comprehensive performance at present. Therefore, high quality superconducting thin films are the basis and key of preparing superconducting single photon detectors. In this paper, the preparation and characterization of ultra-thin NbN thin films and low energy gap NbSi thin films are studied. Ultrathin NbN and NbSi thin films with high quality have been prepared on various substrates. The structure and operation methods of the two preparation systems are introduced in detail, and the detailed preparation processes of the two kinds of thin films are given. The thickness, structure, composition and surface morphology of NbN and NbSi thin films were characterized by energy dispersive X-ray spectrometer (EDX), atomic force microscope (AFM) and scanning electron microscopy (SEM). The superconducting transition temperatures of NbN and NbSi thin films were characterized by liquid helium Dewar measurement system and comprehensive physical property measurement system. The superconducting transition temperature of 4nmNbN films on MgO substrates, 6nmNbN films on Si substrates and 6nmNbN films on Si-SiOx substrates is more than 12.5 K, 7.4 K and 7.38 K, respectively. NbSi thin films were prepared by sputtering pressure and the distance between target and substrate. The composition of the thin film is NB / 65 / Si / 30, and the superconducting transition temperature is 3K, which lays a good foundation for the development of infrared and far-infrared single-photon superconducting detectors. The thickness of the thin films is estimated by measuring the square resistance method. It provides a quick and convenient method for measuring the thickness of ultrathin film, and has been applied to the preparation of single photon detector of superconducting nanowires, and good results have been obtained.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TM26;TB383.2

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相關(guān)碩士學(xué)位論文 前1條

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本文編號：1695468