• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Analysis of properties of krypton ion-implanted Zn-polar ZnO thin films?

    2021-09-28 02:18:28QingFenJiang姜清芬JieLian連潔MinJuYing英敏菊MingYangWei魏銘洋ChenLinWang王宸琳andYuZhang張裕
    Chinese Physics B 2021年9期
    關(guān)鍵詞:張裕清芬

    Qing-Fen Jiang(姜清芬),Jie Lian(連潔),?,Min-Ju Ying(英敏菊),Ming-Yang Wei(魏銘洋),Chen-Lin Wang(王宸琳),and Yu Zhang(張裕)

    1School of Information Science and Engineering,Shandong Provincial Key Laboratory of Laser Technology and Application,Shandong University,Jinan 250100,China

    2Key Laboratory of Beam Technology of Ministry of Education,College of Nuclear Science and Technology,Beijing Normal University,Beijing 100875,China

    Keywords:polar ZnO film,molecular beam epitaxy,Kr implantation,optical properties,bandgap

    1.Introduction

    Zinc oxide(ZnO)material is a wide bandgap semiconductor with high exciton binding energy(60 meV),[1–3]which has broad prospects in many applications such as photodetector,[4]catalysts,[5]and solar cells.[6]Simultaneously,the adjustment of optical properties like bandgap is an essential key to the photoelectric devices with higher requirements than the intrinsic ZnO materials.The ZnO has opposite polarization surfaces due to the lack of inverse symmetry of the c axis,[7]namely,the O-polar ZnO and Zn-polar ZnO.The opposite polar surfaces have been reported to produce a different influences on optical,chemical,and electrical properties.[8,9]Compared with O-polar ZnO the Zn-polar ZnO has strong ability to absorb ultraviolet light and better photocatalytic performance,making it more suitable for being applied to short-wave optoelectronic devices.[10,11]For these reasons,we investigate ion implantation’s effect on the different polar ZnO materials separately.[12]

    Among many methods of preparing ZnO materials,[13,14]molecular beam epitaxy(MBE)is the most advanced technique for growing high-quality crystal films on substrates.Its advantage is that the composition of film can be adjusted rapidly with the change of source.[15]In this paper,the MBE is used to form Zn polar ZnO films.

    Ion implantation is a non-equilibrium renewable semiconductor doping technique that introduces doped elements and defects into crystalline materials.[16]Compared with other chemical doping methods,it has good controllability.Ion implantation changes the compositions,structures,and properties of the materials,and then optimizes their properties to obtain some new excellent properties.[17,18]

    To expand ZnO materials’practical application,it is crucial to change ZnO thin films’properties,such as adjusting the optical bandgap and others.The selection of process parameters and dopants have an essential influence on the microstructure and optical properties of films.The doping of ZnO materials has attracted more and more attention.[19,20]In previous studies,various dopants from metal elements like Ga,[21]Al,[22]and rare earth elements like Eu[23]and Er[14]have been doped into ZnO materials.The studies have shown that doping has a significant influence on the optoelectronic and magnetic properties of ZnO materials.It has guiding significance for the application of ZnO materials.However,there are few studies on Kr ion-implanted polar ZnO materials.Krypton is chemically inert.Previously,Ying et al.[24]investigated the effects on magnetic properties of krypton ion-implanted Znpolar ZnO materials,and ion implantation can result in the change of optical properties,which are critical for the application of materials.[25]Therefore,it is necessary to study the optical properties of krypton ion-implanted Zn-polar ZnO films.

    In the present article,the effects of Kr doping on structure,surface morphology,and optical properties of Zn-polar ZnO thin film are investigated in detail.The results indicate that the Kr ion implantation affects the structure and properties of Zn-polar ZnO film.The change of optical properties may be due to the structural changes caused by ion implantation.This research offers a guideline to judge whether the Kr-doped Zn-polar ZnO thin films can be applied to new photoelectric devices.

    2.Experimental methods

    High-quality Zn-polar ZnO films were fabricated on sapphire substrates through the MBE method.[26]The thickness for each of the films was 300 nm.The substrates were exposed to an oxygen plasma(270 W/1.5 sccm)at 500°C for 30 min.This step was done to obtain a uniform oxygen-terminated surface.Next,a thin MgO buffer layer was produced at 500°C,and followed by a ZnO buffer layer and epilayer growth at 450°C and 650°C,respectively.[12]It was shown that rock salt-MgO layers grown in the typical Stranski–Krastanov pattern produce Zn-polar ZnO.[27]Three Zn-polar ZnO samples were prepared and the AFM results verified that the samples are Zn-polar films.[28]The Kr ions were injected into the films by ion implantation under vacuum condition.Sample 1 is an undoped Zn-polar ZnO film.Sample 2 and sample 3 have Kr-implanted concentrations of about 1×1020cm?3and 5×1020cm?3,denired as Kr 1E20 and Kr 5E20.The concentrations of 1×1020cm?3and 5×1020cm?3were almost uniform at depths 10

    Fig.1.Summed implantation distribution profiles of Kr ions.

    The sample morphology was analyzed using AFM(Nanosurf,Switzerland).The D8 Advance system XRD(xray wavelengthλ=1.51?A)was used for making structural analysis in a 2θrange from 20°to 60°.Since ZnO has strong absorption in the ultraviolet band,absorption spectra were performed in a wavelength range of 325 nm–500 nm with a double beam spectrometer(UV-3600,Shimadzu).The PL spectral testing was done using a He–Cd laser(325 nm,30 mW),which served as an excitation source.

    The SE was used to characterize the optical properties of Zn-polar ZnO films.It is an effective tool used to characterize nanostructures’optical properties with its accuracy and non-destructive properties.[29–31]The parameters were acquired from the parameters(Ψ,Δ)which are related to reflection coefficients of the sample,rpand rs,respectively for p-polarized light and s-polarized light by

    In recent studies of ZnO materials’optical properties,it is commonly utilized to accurately acquire film parameters by varying the films’polarization states and employing suitable dispersion models.[32]After inversion operations,the SE results provide the spectral dielectric function,ZnO layer thickness,and surface roughness thickness.The SE measurements were performed in a wavelength range of 245 nm–450 nm(5.06 eV–2.75 eV)in steps of 0.6 nm and at an incident angle of 65°.The above experiments were carried out at room temperature.

    3.Results and discussion

    Figure 2 shows the XRD patterns of samples inθ–2θgeometry.All the films are of c axis out-of-plane oriented with only ZnO(0002)diffraction peak,indicating that the prepared samples are all high-quality samples.Compared with pure ZnO materials,no other diffraction peaks in the XRD pattern indicate that Kr ion implantation does not induce any additional phase.The values of inter-planar spacing and the full width of half maximum(FWHM)of samples are listed in Table 1.The inter-planar spacing(d)is calculated by Bragg’s relation[33]

    where d is the interplanar distance,n is an integer,andθis the diffraction half angle.Comparing with the undoped Znpolar ZnO film,the increase of d and FWHM indicate that the majority of Kr ions are located at the grain boundaries for samples and a small part of Kr ions enter into the grain lattice,thus causing the lattice to expand.The results of the study are consistent with previously reported conclusions.[24]

    The three-dimensional AFM images of undoped and Krimplanted Zn-polar ZnO films are illustrated in Figs.3(a)–3(c).The results show that all the samples have a pit surface structure.The surface structure has changed obviously after implantation and different ion concentration also affects the surface appearance.As the Kr ion implantation concentration increases,the surface pits become more pronounced.The results are consistent with the observations that the majority of Kr ions are located at the grain boundaries of Zn-polar ZnO film.The roughness for each of three thin films is gained via the arithmetic square root(Ra),and the roughness values of Zn-polar undoped film,Kr 1E20 sample,and Kr 5E20 sample are 9.5 nm,12.7 nm,and 14.9 nm,respectively.Since the test results show that the roughness cannot be ignored,a roughness layer is required during subsequent model building in the SE work.

    Table 1.Values of 2θ,interplanar spacing,and FWHM of samples.

    Fig.3.Three-dimensional images of three samples:(a)Zn-polar undoped,(b)Kr 1E20,(c)Kr 5E20.

    Fig.4.Absorption spectra of three samples,with inset showing Tauc plot.

    Figure 4 shows the absorption spectra of samples obtained by a double beam spectrometer.As can be seen,there is high absorption in the ultravioletregion.The sharp drop in the absorption at about 375 nm is associated with the transition between the valence band and conduction band.[34]Comparing with the undoped sample,the results show that the absorption of Kr implantation sample is enhanced.

    The bandgap can be figured out from the basic absorption edge of the sample.As a direct bandgap semiconductor,the ZnO material has a bandgap that can be estimated from the following formula:[14]

    where A is a constant,Egis the bandgap energy,h is Planck’s constant,andυis the frequency.The Egcan be obtained by drawing(αhν)2versus energy and extending the straight-line portion of plot to the transverse axis.The results are given in the inset of Fig.4.It can be seen from the inset in Fig.4 that the bandgap energies of Zn-polar undoped,Kr 1E20,and Kr 5E20 samples are 3.16 eV,3.13 eV,and 3.12 eV,respectively.

    Figure 5 shows room temperature photoluminescence spectra.The PL peaks for the Zn-polar undoped,Kr 1E20,and Kr 5E20 samples are located at 3.29 eV,3.27 eV,and 3.27 eV,respectively.These peaks are induced by exciton relaxation and associated with near-edge emission which is caused by the radiative recombination of holes in the valence band with electrons in the conduction band.[35]Compared with the undoped sample,Kr-implanted Zn-polar ZnO film’s PL peak shifts toward lower energy.And this phenomenon of redshift may be due to the narrowing of the bandgap.[36]No impurities are introduced into the film for the undoped sample,and no other stray peaks exist.The weak impurity peaks in the result may be from the experimental process.The PL peaks for the Znpolar undoped,Kr 1E20,and Kr 5E20 samples have different FWHMs,which are 0.363 eV,0.334 eV,and 0.089 eV,respectively.The PL peaks are narrowed after Kr ion implantation.

    Fig.5.PL spectra of three samples.

    The influences of Kr implantation on the optical properties of Zn-polar ZnO films are investigated by spectroscopic ellipsometry.The results of SE are obtained by establishing a structure model and dispersion model.Before modeling,the optical constants of the sapphire substrate are measured.Since the three samples’roughness values cannot be ignored,a five-layer model(air/roughness/implanted ZnO/ZnO/sapphire)needs to be established in the fitting process.Figure 6 displays the model of sample.For the sample without ion implantation,a four-layer model is established.The rough layer,which consists of 50%voids and 50%ZnO,is built with a Bruggeman effective medium approximation.[37]

    Fig.6.Schematic diagram of structural model.

    Fig.7.Ellipsometric experimental data(point)and simulated data(line)for(a)Zn-polar undoped sample,(b)Kr 1E20 sample,and(c)Kr 5E20 sample,with blue color denotingψand red color referring toΔ.

    To acquire optical parameters successfully for the ionimplanted layer,the measured spectra are parameterized by using Tauc–Lorentz oscillators.[38]The Tauc–Lorentz oscillator is defined by[ε1(∞),A,C,Eg,and En0],and they involve the effects of high energy,amplitude parameter,a broadening parameter,bandgap energy,and peak transition energy,respectively.The TL dispersion mode gives the expression of the dielectric function as shown below:[39]

    where A is the amplitude parameter,C is the broadening parameter,and En0represents the peak transition energy.The optimal fitting parameters are listed in Table 2,and the fitting results of films are shown in Fig.7.The measured data are represented by points,and the simulated data are denoted by solid lines.Then,the TL model’s validity can be confirmed by the small value of the mean squared error(MSE).[32]The MSE and other parameters are given in Table 3.The roughness obtained from the AFM is also presented in Table 3.The experimental data are in agreement with the fitted data,and the thickness result is consistent with 300 nm,which indicates the fitting’s correctness.

    As shown in Fig.8,the refractive index(n)and the extinction coefficient(k)are obtained from the SE fitting results.The refractive index is represented by a dotted line,and the extinction coefficient is denoted by a solid line.As can be seen in the figure,the refractive index of the ZnO film decreases with the Kr doping increasing,while the extinction coefficient increases.As the Kr ion implantation concentration increases,the refractive index of the film decreases and the extinction coefficient also increases.With the Kr implantation,the fullwidth at half maximum,the grain size,and the surface density of samples change.These changes lead the extinction coefficient to change.[40,41]Thus,the ion implantation can be used to regulate the refractive index of polar ZnO films,which has significant application value for designing the integrated optical devices.[42]

    Table 2.Optimal fitting parameters in TL dispersion mode.

    Table 3.Parameters of samples obtained by SE and AFM.

    Fig.8.Variations of refractive index n(dotted line)and extinction coefficient k(solid line)with energy.

    The dielectric function is of great importance in studying the optical properties,especially the imaginary part of the dielectric function.[43]The expression for the dielectric function and the formula to calculate them are shown as follows:

    whereε1andε2are real and imaginary pars of the dielectric function,respectively.Theε2is related to electron transition energy between the valence band and the conduction band.[39]Figure 9 shows the imaginary parts’spectra of the dielectric function.It can be seen thatε2for each of all samples shows a tendency of first increase and then decrease.

    The second-derivative spectra of the imaginary part of dielectric function are computed to accurately obtain the bandgap of samples as illustrated in Figs.10(a)–10(c).It can be seen from Fig.10 that the bandgap has a redshift with the Kr implantation,which is in agreement with the result of absorption spectra.And this might be attributed to variations in grain size,structural parameters,etc.[44]The shifting in Egvalue indicates that the bandgap can be regulated by injecting Kr ions into polar ZnO materials.

    Fig.9.Variations of imaginary part of the dielectric function with energy for three different samples.

    Fig.10.Second-derivative spectra of imaginary part for(a)Zn-polar undoped sample,(b)Kr 1E20 sample,and(c)Kr 5E20 sample.

    4.Conclusions

    The Kr ions are implanted into high-quality Zn-polar ZnO films fabricated through the MBE method on sapphire substrates by ion implantation.The XRD results show that the samples are of good quality.The AFM results show that the surface morphology of Zn-polar ZnO film is changed after Kr implantation.Moreover,the optical properties are gained by absorption spectrum,PL,and SE.The results show that the absorption increases and the bandgap decreases with ion implantation.

    Moreover,the Kr ion implantation concentration also affects the properties of the film.The films’refractive index decreases with the Kr ion implantation concentrationincreasing In short,Kr ion implantation regulates the properties of Znpolar ZnO films.This study can conduce to the photoelectric applications of ion-implanted ZnO thin films.

    Acknowledgment

    We are deeply grateful to Miss Min-Ju Ying for her valuable support.

    猜你喜歡
    張裕清芬
    Diaopu Mutton刁鋪羊肉
    清芬正氣朱自清
    華人時刊(2022年13期)2022-10-27 08:56:22
    清芬凌霜
    詠荷
    周仲埕
    書香兩岸(2020年3期)2020-06-29 12:33:45
    張裕解百納:進(jìn)入第九代,邁向全球化
    食品界(2018年5期)2018-06-21 17:51:54
    “葡萄酒巨頭”十年間不進(jìn)反退 張裕市值已被茅臺甩開8000億
    投資者報(2018年18期)2018-05-09 07:55:40
    氣韻生動 瀟灑自然——柳清芬書法印象
    丹青少年(2017年5期)2017-02-06 03:03:46
    張裕發(fā)力白蘭地多元化布局
    食品界(2016年9期)2016-11-08 17:16:43
    炒股引發(fā)親情崩盤
    晚報文萃(2016年3期)2016-05-03 08:08:55
    大型黄色视频在线免费观看| 天天操日日干夜夜撸| 丝瓜视频免费看黄片| 怎么达到女性高潮| 免费观看人在逋| 久久人人97超碰香蕉20202| 黄色毛片三级朝国网站| 久久精品成人免费网站| 午夜精品国产一区二区电影| 午夜精品久久久久久毛片777| 黄片小视频在线播放| 午夜精品国产一区二区电影| 国产精品一区二区在线不卡| 精品福利永久在线观看| 国产又爽黄色视频| 亚洲中文字幕日韩| 真人做人爱边吃奶动态| 少妇的丰满在线观看| 大型av网站在线播放| 国产xxxxx性猛交| 成人特级黄色片久久久久久久| 一级毛片精品| 国产亚洲av高清不卡| 在线观看日韩欧美| av天堂在线播放| 99精品在免费线老司机午夜| 久久久久久久午夜电影 | 欧美日韩精品网址| 免费久久久久久久精品成人欧美视频| a级毛片在线看网站| 日韩 欧美 亚洲 中文字幕| 成年人午夜在线观看视频| 亚洲一区高清亚洲精品| 亚洲第一欧美日韩一区二区三区| 精品人妻熟女毛片av久久网站| 999久久久精品免费观看国产| 丰满迷人的少妇在线观看| 成年人黄色毛片网站| 国产精品二区激情视频| 丰满饥渴人妻一区二区三| 中文字幕最新亚洲高清| 啪啪无遮挡十八禁网站| 精品国产一区二区三区四区第35| 丝袜美足系列| 一级片免费观看大全| 欧美老熟妇乱子伦牲交| 国产亚洲av高清不卡| 首页视频小说图片口味搜索| 1024视频免费在线观看| av视频免费观看在线观看| 国产精品亚洲一级av第二区| 中文字幕最新亚洲高清| 91国产中文字幕| 国产91精品成人一区二区三区| 国产精品一区二区精品视频观看| 夫妻午夜视频| 久久久久国内视频| 国产免费av片在线观看野外av| 91九色精品人成在线观看| 精品福利永久在线观看| 亚洲精品久久成人aⅴ小说| 国产精品1区2区在线观看. | 动漫黄色视频在线观看| 国产精品久久电影中文字幕 | 国产在线观看jvid| 国内久久婷婷六月综合欲色啪| 这个男人来自地球电影免费观看| 99热只有精品国产| 天天躁日日躁夜夜躁夜夜| 国产成人欧美在线观看 | 日韩一卡2卡3卡4卡2021年| 99热只有精品国产| 国产野战对白在线观看| 妹子高潮喷水视频| 91精品国产国语对白视频| 精品熟女少妇八av免费久了| 久久人妻福利社区极品人妻图片| av在线播放免费不卡| 在线观看免费视频日本深夜| 50天的宝宝边吃奶边哭怎么回事| 如日韩欧美国产精品一区二区三区| 日本黄色日本黄色录像| 欧美+亚洲+日韩+国产| 热re99久久国产66热| 18禁裸乳无遮挡动漫免费视频| 亚洲av日韩在线播放| 亚洲视频免费观看视频| 99国产精品99久久久久| 夜夜夜夜夜久久久久| 亚洲av第一区精品v没综合| 日韩成人在线观看一区二区三区| 免费日韩欧美在线观看| 国产亚洲欧美精品永久| 久久精品成人免费网站| 成年人免费黄色播放视频| 91成人精品电影| 欧美激情久久久久久爽电影 | 亚洲第一欧美日韩一区二区三区| 日韩欧美免费精品| 精品国产一区二区三区四区第35| 成年人午夜在线观看视频| 少妇被粗大的猛进出69影院| 国产高清国产精品国产三级| 国产精品永久免费网站| 国产男女超爽视频在线观看| 亚洲精品国产精品久久久不卡| 午夜福利欧美成人| 国产深夜福利视频在线观看| 亚洲三区欧美一区| 欧美日韩av久久| 激情在线观看视频在线高清 | 色94色欧美一区二区| 亚洲精品一二三| 一本一本久久a久久精品综合妖精| 一进一出好大好爽视频| 亚洲第一av免费看| av线在线观看网站| 嫩草影视91久久| av中文乱码字幕在线| 欧美av亚洲av综合av国产av| 自线自在国产av| 久久久久久免费高清国产稀缺| 精品国产国语对白av| 看片在线看免费视频| 狂野欧美激情性xxxx| 国产区一区二久久| 别揉我奶头~嗯~啊~动态视频| 麻豆av在线久日| tocl精华| 青草久久国产| 一级片免费观看大全| 一级片免费观看大全| 交换朋友夫妻互换小说| а√天堂www在线а√下载 | 午夜久久久在线观看| 狂野欧美激情性xxxx| 国产97色在线日韩免费| 亚洲欧美激情综合另类| 一区在线观看完整版| 男人的好看免费观看在线视频 | 午夜免费鲁丝| 黄色毛片三级朝国网站| 无限看片的www在线观看| 日韩免费高清中文字幕av| 日日夜夜操网爽| 看免费av毛片| 女人爽到高潮嗷嗷叫在线视频| 9热在线视频观看99| 久久婷婷成人综合色麻豆| 纯流量卡能插随身wifi吗| 丝瓜视频免费看黄片| 久久久国产欧美日韩av| 女人高潮潮喷娇喘18禁视频| 99国产极品粉嫩在线观看| 搡老岳熟女国产| 午夜福利一区二区在线看| 欧美黑人精品巨大| 国产精品免费一区二区三区在线 | 精品人妻熟女毛片av久久网站| 欧美av亚洲av综合av国产av| 午夜福利视频在线观看免费| 国产精品久久久人人做人人爽| 亚洲成人国产一区在线观看| 国产欧美亚洲国产| 久久久水蜜桃国产精品网| 亚洲精品一二三| 国产一区二区三区在线臀色熟女 | 超碰成人久久| 亚洲成人手机| www日本在线高清视频| 国产精品98久久久久久宅男小说| 男女高潮啪啪啪动态图| 91成年电影在线观看| 国产精品免费一区二区三区在线 | 高清毛片免费观看视频网站 | 欧美 日韩 精品 国产| 超碰97精品在线观看| 中文字幕制服av| 乱人伦中国视频| 极品少妇高潮喷水抽搐| 亚洲少妇的诱惑av| tube8黄色片| 国产淫语在线视频| 精品人妻熟女毛片av久久网站| 精品久久久久久久毛片微露脸| 狠狠婷婷综合久久久久久88av| 国产黄色免费在线视频| 国产精品秋霞免费鲁丝片| 美女 人体艺术 gogo| 黄色片一级片一级黄色片| 成年女人毛片免费观看观看9 | 国产精品永久免费网站| 国产精品欧美亚洲77777| 精品久久久久久久久久免费视频 | 视频区图区小说| 自拍欧美九色日韩亚洲蝌蚪91| 欧美日韩福利视频一区二区| 国产aⅴ精品一区二区三区波| 精品第一国产精品| 日本vs欧美在线观看视频| √禁漫天堂资源中文www| 国产免费男女视频| 国产高清视频在线播放一区| 国产亚洲欧美在线一区二区| 国产成人av教育| 91精品国产国语对白视频| 精品一区二区三区视频在线观看免费 | 夜夜爽天天搞| 高清av免费在线| 国产精品国产高清国产av | 欧美成人免费av一区二区三区 | 国产一卡二卡三卡精品| 一级片免费观看大全| 欧洲精品卡2卡3卡4卡5卡区| 老司机亚洲免费影院| 一a级毛片在线观看| 男女下面插进去视频免费观看| 亚洲第一欧美日韩一区二区三区| 高清欧美精品videossex| 精品亚洲成国产av| 精品国产乱码久久久久久男人| 久久精品国产99精品国产亚洲性色 | 超碰97精品在线观看| 成人影院久久| 18禁裸乳无遮挡动漫免费视频| 久久久国产一区二区| 丰满人妻熟妇乱又伦精品不卡| 国产激情欧美一区二区| 热99国产精品久久久久久7| 国产精品亚洲一级av第二区| 亚洲熟女毛片儿| 婷婷精品国产亚洲av在线 | 亚洲五月婷婷丁香| 18禁国产床啪视频网站| 黑丝袜美女国产一区| 日韩人妻精品一区2区三区| 欧美日韩亚洲国产一区二区在线观看 | 搡老乐熟女国产| 国产精品99久久99久久久不卡| 一本大道久久a久久精品| 99国产精品99久久久久| 亚洲国产欧美网| 最新美女视频免费是黄的| 色播在线永久视频| 亚洲欧美日韩另类电影网站| 日本五十路高清| 无遮挡黄片免费观看| 国产精品久久久人人做人人爽| 国产精品av久久久久免费| 成年人黄色毛片网站| 首页视频小说图片口味搜索| 成人影院久久| a级毛片黄视频| 国产一区有黄有色的免费视频| 国产一区二区三区在线臀色熟女 | 香蕉国产在线看| av网站在线播放免费| 日韩视频一区二区在线观看| 欧美成狂野欧美在线观看| 91老司机精品| 韩国精品一区二区三区| 精品久久久久久久毛片微露脸| 中文字幕高清在线视频| 欧美乱码精品一区二区三区| 免费不卡黄色视频| 黄色丝袜av网址大全| 91九色精品人成在线观看| 黄色 视频免费看| a级片在线免费高清观看视频| 亚洲七黄色美女视频| 精品久久久久久电影网| 久久青草综合色| 久久久国产精品麻豆| 啦啦啦 在线观看视频| 黄片大片在线免费观看| √禁漫天堂资源中文www| 亚洲国产欧美网| www.自偷自拍.com| 久久久水蜜桃国产精品网| 国产黄色免费在线视频| 美女扒开内裤让男人捅视频| 岛国在线观看网站| 午夜福利欧美成人| 久久精品国产亚洲av高清一级| 久久久久久亚洲精品国产蜜桃av| 丝袜美足系列| 精品人妻1区二区| 亚洲人成77777在线视频| 国产极品粉嫩免费观看在线| 亚洲精品久久午夜乱码| 在线观看www视频免费| 国产91精品成人一区二区三区| 国产精品 国内视频| 少妇的丰满在线观看| 国产在线精品亚洲第一网站| 在线观看舔阴道视频| 欧美国产精品va在线观看不卡| 搡老岳熟女国产| 久久久久久久久久久久大奶| www.熟女人妻精品国产| 国产精品1区2区在线观看. | 精品人妻1区二区| 久久中文字幕人妻熟女| 99久久精品国产亚洲精品| 99久久99久久久精品蜜桃| 韩国精品一区二区三区| 人人妻人人澡人人爽人人夜夜| 男人的好看免费观看在线视频 | 午夜福利一区二区在线看| 啪啪无遮挡十八禁网站| 大码成人一级视频| 欧美精品亚洲一区二区| 在线观看一区二区三区激情| 丝袜美腿诱惑在线| 99久久综合精品五月天人人| 看片在线看免费视频| 久久久久久免费高清国产稀缺| 丰满的人妻完整版| 亚洲av熟女| 成人三级做爰电影| 中文字幕高清在线视频| 午夜影院日韩av| 免费高清在线观看日韩| 精品欧美一区二区三区在线| 色播在线永久视频| 亚洲全国av大片| 天天添夜夜摸| 国产精品秋霞免费鲁丝片| 成人永久免费在线观看视频| 亚洲欧美激情在线| 久久久精品免费免费高清| 日韩大码丰满熟妇| 欧美大码av| 国产亚洲精品一区二区www | 成人手机av| 夜夜躁狠狠躁天天躁| 精品电影一区二区在线| av有码第一页| 在线观看免费午夜福利视频| 国产成人免费观看mmmm| 久久精品国产综合久久久| 搡老岳熟女国产| 亚洲第一青青草原| 丁香欧美五月| 亚洲av日韩精品久久久久久密| 两人在一起打扑克的视频| 国产精品二区激情视频| 国产欧美日韩综合在线一区二区| 欧美久久黑人一区二区| 午夜91福利影院| 亚洲精品国产区一区二| 国产一卡二卡三卡精品| 亚洲黑人精品在线| 亚洲综合色网址| 99国产精品一区二区三区| 国产又爽黄色视频| 亚洲五月天丁香| 国产精品一区二区在线不卡| 一级黄色大片毛片| 99在线人妻在线中文字幕 | 成人精品一区二区免费| 老熟妇仑乱视频hdxx| 亚洲熟妇中文字幕五十中出 | 久久久精品国产亚洲av高清涩受| 99精品在免费线老司机午夜| 午夜视频精品福利| 国产午夜精品久久久久久| 91国产中文字幕| 国产aⅴ精品一区二区三区波| 国产亚洲一区二区精品| 人妻一区二区av| 国产精品成人在线| 最新美女视频免费是黄的| 免费在线观看影片大全网站| 一二三四社区在线视频社区8| 精品国产乱码久久久久久男人| 免费不卡黄色视频| 女人爽到高潮嗷嗷叫在线视频| 亚洲成人免费av在线播放| 午夜亚洲福利在线播放| 老司机午夜福利在线观看视频| 老司机深夜福利视频在线观看| 精品久久久久久,| 国产成人精品无人区| 高清av免费在线| 欧美不卡视频在线免费观看 | 成人国语在线视频| 无限看片的www在线观看| 国产在线观看jvid| 亚洲五月天丁香| 搡老乐熟女国产| 建设人人有责人人尽责人人享有的| 久久中文看片网| 欧美精品一区二区免费开放| 亚洲情色 制服丝袜| 妹子高潮喷水视频| 十八禁网站免费在线| 国产亚洲精品久久久久5区| 免费在线观看黄色视频的| 男女高潮啪啪啪动态图| 亚洲中文日韩欧美视频| 国产成人系列免费观看| 超色免费av| 亚洲av片天天在线观看| 国产亚洲精品第一综合不卡| 国产成人精品无人区| 女人被狂操c到高潮| 国产精品一区二区精品视频观看| 国产高清激情床上av| 大香蕉久久成人网| 欧美乱码精品一区二区三区| 少妇被粗大的猛进出69影院| 18禁裸乳无遮挡免费网站照片 | 18禁裸乳无遮挡免费网站照片 | 欧美乱妇无乱码| 精品少妇久久久久久888优播| 国产精品影院久久| 欧美日韩乱码在线| av一本久久久久| 欧美日韩黄片免| 成人亚洲精品一区在线观看| 国产成人免费观看mmmm| 午夜激情av网站| 大香蕉久久网| 日本vs欧美在线观看视频| 亚洲熟女毛片儿| 久久久国产精品麻豆| 久久草成人影院| 亚洲熟女毛片儿| 女性生殖器流出的白浆| 国产单亲对白刺激| 亚洲欧美精品综合一区二区三区| 亚洲精品一二三| 热99re8久久精品国产| 国产精品国产高清国产av | 两人在一起打扑克的视频| 9热在线视频观看99| 欧美日本中文国产一区发布| 12—13女人毛片做爰片一| 高清在线国产一区| 国产精品98久久久久久宅男小说| 嫩草影视91久久| 亚洲男人天堂网一区| 女人精品久久久久毛片| 丰满饥渴人妻一区二区三| 国产淫语在线视频| 国产真人三级小视频在线观看| 夜夜爽天天搞| 亚洲精品av麻豆狂野| 极品少妇高潮喷水抽搐| 99国产精品一区二区蜜桃av | 美女国产高潮福利片在线看| 热99久久久久精品小说推荐| 欧美色视频一区免费| 久久精品亚洲精品国产色婷小说| av欧美777| 免费在线观看黄色视频的| 岛国在线观看网站| 亚洲av日韩精品久久久久久密| 亚洲欧洲精品一区二区精品久久久| 天天躁夜夜躁狠狠躁躁| 麻豆av在线久日| 女人爽到高潮嗷嗷叫在线视频| 宅男免费午夜| 亚洲免费av在线视频| 国产视频一区二区在线看| 亚洲精品粉嫩美女一区| 女人精品久久久久毛片| 国产无遮挡羞羞视频在线观看| 国产av精品麻豆| 9色porny在线观看| 人人妻,人人澡人人爽秒播| 免费看十八禁软件| 热re99久久国产66热| 美女高潮喷水抽搐中文字幕| 大片电影免费在线观看免费| 黑人巨大精品欧美一区二区蜜桃| 免费看十八禁软件| 757午夜福利合集在线观看| 久久精品aⅴ一区二区三区四区| 欧美精品一区二区免费开放| 亚洲va日本ⅴa欧美va伊人久久| 人妻一区二区av| 女人被狂操c到高潮| 飞空精品影院首页| 亚洲一码二码三码区别大吗| 99久久99久久久精品蜜桃| 国产精品九九99| 看免费av毛片| 日韩欧美三级三区| 亚洲综合色网址| 无遮挡黄片免费观看| 亚洲成a人片在线一区二区| 午夜免费成人在线视频| 亚洲人成电影观看| 老司机深夜福利视频在线观看| 国产男靠女视频免费网站| 一边摸一边抽搐一进一小说 | 国产免费av片在线观看野外av| 在线观看日韩欧美| 婷婷成人精品国产| 一级作爱视频免费观看| 不卡一级毛片| 久久天躁狠狠躁夜夜2o2o| 好看av亚洲va欧美ⅴa在| 久久精品人人爽人人爽视色| 国产成人免费无遮挡视频| 亚洲成av片中文字幕在线观看| 高清在线国产一区| 午夜福利乱码中文字幕| 国产亚洲欧美精品永久| 国产一区有黄有色的免费视频| 日本wwww免费看| 三上悠亚av全集在线观看| 中国美女看黄片| 757午夜福利合集在线观看| 中文字幕人妻丝袜制服| 搡老熟女国产l中国老女人| 国产一区二区三区在线臀色熟女 | 色综合婷婷激情| 黄色视频不卡| 久久热在线av| 久久亚洲精品不卡| 一级片'在线观看视频| 午夜福利欧美成人| 在线播放国产精品三级| 巨乳人妻的诱惑在线观看| 国产亚洲欧美精品永久| 另类亚洲欧美激情| 成人影院久久| 午夜免费观看网址| 正在播放国产对白刺激| 国产精品免费一区二区三区在线 | 精品福利观看| 啪啪无遮挡十八禁网站| 国产视频一区二区在线看| 这个男人来自地球电影免费观看| 精品少妇一区二区三区视频日本电影| 中国美女看黄片| 麻豆乱淫一区二区| 香蕉国产在线看| 少妇粗大呻吟视频| 久久久国产成人免费| 成人av一区二区三区在线看| 99香蕉大伊视频| 日韩制服丝袜自拍偷拍| 国产区一区二久久| 亚洲国产毛片av蜜桃av| 婷婷丁香在线五月| 日韩精品免费视频一区二区三区| 亚洲精品国产一区二区精华液| 国产一区二区三区综合在线观看| 亚洲午夜精品一区,二区,三区| 日韩大码丰满熟妇| 男女午夜视频在线观看| 久久人人爽av亚洲精品天堂| а√天堂www在线а√下载 | av片东京热男人的天堂| 免费在线观看完整版高清| 国产精品久久久久成人av| 国产精品偷伦视频观看了| 国产野战对白在线观看| 国产成人av激情在线播放| 欧美日韩乱码在线| 悠悠久久av| 亚洲国产中文字幕在线视频| 亚洲av电影在线进入| 亚洲专区国产一区二区| 国产亚洲欧美98| 亚洲成人国产一区在线观看| 老司机深夜福利视频在线观看| 一区在线观看完整版| 国产一区在线观看成人免费| 日日爽夜夜爽网站| 午夜福利在线观看吧| 自线自在国产av| 成人18禁在线播放| 午夜福利免费观看在线| 黄网站色视频无遮挡免费观看| 成人国语在线视频| 一二三四社区在线视频社区8| 美女国产高潮福利片在线看| 99久久国产精品久久久| 亚洲成人国产一区在线观看| av不卡在线播放| 别揉我奶头~嗯~啊~动态视频| 久热这里只有精品99| 天天躁日日躁夜夜躁夜夜| 午夜精品在线福利| 一级a爱片免费观看的视频| 国产成人免费无遮挡视频| 久久久久国内视频| 午夜福利视频在线观看免费| av国产精品久久久久影院| 夜夜爽天天搞| 国产日韩欧美亚洲二区| 免费观看精品视频网站| 久久精品91无色码中文字幕| 久久久国产欧美日韩av| 亚洲精品久久午夜乱码| 一级,二级,三级黄色视频| av天堂在线播放| 久久人人爽av亚洲精品天堂| 69av精品久久久久久| 黑人巨大精品欧美一区二区蜜桃| 久久国产精品人妻蜜桃| 亚洲国产精品一区二区三区在线| 嫩草影视91久久| 国产在线精品亚洲第一网站| 国产伦人伦偷精品视频| 中文字幕制服av| 欧美精品av麻豆av| 男女免费视频国产| 欧美+亚洲+日韩+国产| 国产在线精品亚洲第一网站|