• <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 ?

    Effects of electrical stress on the characteristics and defect behaviors in GaN-based near-ultraviolet light emitting diodes

    2022-06-29 09:23:50YingZheWang王穎哲MaoSenWang王茂森NingHua化寧KaiChen陳凱ZhiMinHe何志敏XueFengZheng鄭雪峰PeiXianLi李培咸XiaoHuaMa馬曉華LiXinGuo郭立新andYueHao郝躍
    Chinese Physics B 2022年6期
    關(guān)鍵詞:陳凱雪峰

    Ying-Zhe Wang(王穎哲) Mao-Sen Wang(王茂森) Ning Hua(化寧) Kai Chen(陳凱)Zhi-Min He(何志敏) Xue-Feng Zheng(鄭雪峰) Pei-Xian Li(李培咸) Xiao-Hua Ma(馬曉華)Li-Xin Guo(郭立新) and Yue Hao(郝躍)

    1Key Laboratory of Wide Bandgap Semiconductor Materials and Devices,School of Microelectronics,Xidian University,Xi’an 710071,China

    2Shanghai Aerospace Electronic Technology Institute,Shanghai 201109,China

    3School of Advanced Materials and Nanotechnology,Xidian University,Xi’an 710071,China

    4School of Physics and Optoelectronic Engineering,Xidian University,Xi’an 710071,China

    Keywords: light emitting diodes,GaN,electrical stress,defect

    1. Introduction

    GaN-based near-ultraviolet (NUV, 320–400 nm) light emitting diodes (LEDs) have received extensive attention in practical applications such as curing,short-distance fiber communications, biosensors, and materials processing.[1–4]Due to the advantages of small dimensions, low power consumption, and environmental protection, the market for NUV LEDs is continuously expanding. However, during operation, some reliability problems, such as optical power (OP)decay,have been the bottleneck for the further development of devices.[5–7]Therefore,it is essential to study the degradation mechanisms of GaN-based NUV LEDs under electrical stress.

    For GaN-based LEDs, it is suggested that electrical stress-induced degradation can be attributed to the generation or the propagation of point defects activated by carrier transport, such as vacancies or anti-site defects.[8–12]In addition,effects of dislocations on device degradation cannot be ignored for NUV LEDs[13–15]due to the lack of In-rich clusters that separate carriers from dislocations.[16]However,the behavior of defects that cause device degradation has yet to be confirmed. The process of defect generation/propagation under electrical stress should be further demonstrated.

    In this work,we investigate the degradation mechanisms of NUV LEDs under electrical stress from the aspect of defects. Under different stress time, the optical and electrical characteristics in NUV LEDs are evaluated by electroluminescence (EL) and current–voltage (I–V) measurement. Meanwhile,the deep level transient spectroscopy(DLTS)measurement is applied to characterize the defect behavior, including defect concentration,energy level,and cross section.From the DLTS results under different filling pulse widths, the defect spatial distribution is analyzed in detail. In addition,photoluminescence (PL) measurement is also introduced to assist in judging the origin of the defect leading to degradation.

    2. Device and experiments

    The experimental analysis was performed simultaneously on five NUV LEDs with a peak emission wavelength of 385 nm from the same wafer.As shown in Fig.1,from bottom to top, the structure consists of a sapphire substrate, an undoped GaN buffer layer,a 900-nm-thick Si-doped n-type GaN layer, a 30-nm-thick n-Al0.05Ga0.95N layer, a 400-nm-thick lightly Si-doped GaN layer, an active region, a 30-nm-thick Mg-doped p-Al0.15Ga0.85N electron blocking layer(EBL),and a 240-nm-thick p-GaN layer. The active region consists of eight-period Si-doped multiple quantum wells (MQWs) using 10-nm-thick GaN barriers and 1-nm-thick In0.07Ga0.93N wells. The chip size is 1143 μm×1143 μm. NUV LEDs were stressed with a constant current of 600 mA,which was twice the nominal operation current (300 mA) and can cause great degradation. In order to be closer to the actual application,the electrical stress was applied under room temperature without any heat dissipation. After electrical stress, the device characteristics and defect behaviors were characterized when the junction temperature returned to room temperature.

    3. Results and discussion

    The kinetics of the optical power decrease in NUV LEDs were investigated during electrical stress using electroluminescence (EL) measurement. As shown in Fig. 2(a), the optical power decreases evidently with the increasing stress time. In GaN-based photoelectric devices, it can be attributed to the increase of non-radiative recombination centers.[17]The electrical characteristics were also characterized usingI–Vmeasurement at room temperature from-10 V to 3 V.It is shown in Fig. 2(b) that the reverse leakage current (Ir) increases by several orders of magnitude after stress. Previous studies demonstrated thatIris associated with the parasitic leakage path.[18]In addition, the current under low forward bias also increases after stress,which can be ascribed to the increase of trap-assisted tunneling (TAT) current.[19]Both non-radiative recombination centers,parasitic leakage paths,and TAT mechanisms are all tightly correlated with defects within or around the active region.[20,21]Therefore,the variation of the defects in NUV LEDs during electrical stress should be pressingly studied.

    Firstly, photoluminescence (PL) measurement was carried out using a He–Cd laser emitting at 325 nm at room temperature to detect and identify the defects in NUV LEDs macroscopically. Different from EL measurement,the results in PL measurement are not related to injection efficiency,making it possible to characterize the defect luminescence characteristics more intuitively.[22]As shown in Fig. 3, the appearance of the band-to-band peak at 3.2 eV indicates that the region detected in PL measurement includes the active region.With the increasing stress time, a yellow luminescence (YL)band centered around 2.2–2.3 eV increases,indicating that the concentration of some defects increases under the stimulation of electrical stress. In the GaN material system, many previous studies demonstrated that the YL band could be attributed to Ga vacancy(VGa)related defects.[23,24]However,the origin of the defects should be further confirmed, and the evolution mechanism of the defects should be studied deeply.

    DLTS measurement,which can quantitatively extract the defect physical parameters,[25]has been applied to investigate the defect behaviors deeply.Figure 4(a)shows the DLTS spectra scanned from 490 K to 60 K with a quiescent bias of-7 V,a filling pulse bias of 2 V,and a filling pulse width of 10 ms.These bias and temperature values were chosen to explore the defects in the n-type active region comprehensively. In our measurement system, the positive and negative peaks are associated with majority-carriers (electron) traps and minoritycarriers (hole) traps, respectively. With the increase of stress time,a positive peak A at~70 K almost has no change. Such a narrow peak at low temperature may not be associated with the defects but with the emission from QW to the conduction band.[26]The activation energy of peak e1 is 0.08 eV,which may be related to the conduction band offset of the In-GaN/GaN quantum well.[27]The slight decrease of peak e1 after stress can reflect the decline of QW quality.

    In this work,more attention should be paid to peaks corresponding to defects in the DLTS spectrum(Fig.4(a)).Under the stimulation of electrical stress,a positive peak e2 at~310 K increases. The activation energy and cross section of defect e2 are extracted from the Arrhenius plot in Fig.4(b),which are 0.47–0.56 eV and 3.2×10-17–2.7×10-16cm2, respectively.In addition,compared with the PL results,the increased peak e2 may correspond to the increased YL peak in the PL spectrum. Combing the YL-related feature with the activation energy,defect e2 can be attributed to VGarelated complex,possibly involving oxygen, e.g., VGa–ON.[10,28,29]Interestingly,during increasing of concentration of defect e2,the concentration of intrinsic defect e3(a positive peak at~460 K)with the activation energy 0.72–0.84 eV and cross section 1.8×10-17–9.8×10-16cm2decreases. The linear relationship in the inset of Fig.4(a)suggests a direct correlation between the defects e2 and e3. In other words,the increase of concentration of defect e2 after stress may result from the decreasing concentration of defect e3.

    Moreover,in the GaN system,besides the non-interacting point defects, linearly arranged defects such as point defects along dislocations also need to be focused on. The noninteracting and linear arranged point defects will exhibit completely different behaviors. It is difficult to identify defects accurately merely through the activation energy. Therefore,it is significant to analyze the defect spatial configuration using DLTS measurement under different filling pulse widths.[30]For the non-interacting point defects, the concentration of occupied defect states (nT) corresponding to the DLTS signal will be exponentially correlated to the filling pulse width(tp):[31]

    whereτis the characteristic time. As shown in Fig. 5, both the DLTS signals of defects e2 and e3 are logarithmically correlated to the filling pulse width, indicating that these two defects are point defects along dislocations. The evolution of defects develops around dislocations, possibly due to the relatively concentrated current flow path.[32,33]The characteristic of the electron trap and its contribution to the yellow band peak further demonstrate that defect e2 is likely related to VGaand oxygen related complex(e.g.,VGa–ON)along dislocation.[34–36]This defect may act as the non-radiative recombination center and parasitic leakage path and then degrade NUV LEDs.

    So far, there is still a question about the origin of the intrinsic defect e3 and the evolution process between these two defects. For the defect e3 with the activation energy of 0.72–0.84 eV, there are some possible origins such as VGa–ON–H,[37]VN–H,[38]VGa–VN.[23]Among them, the formation energies of VN–H and VGa–VNare very high in the n-type region,[23,39]which leads to the little possibility of formation during growth. It is more likely to attribute the intrinsic defect e3 to VGa–ON–H, mainly for three reasons. Firstly, it is now well accepted that oxygen and hydrogen can often be the background contaminants during growth,[40]and VGais likely to form a complex with impurities like O and H during growth due to the low formation energy.[24,41]Secondly,the defect luminescence will decrease when the defects are passivated with H.[42]This phenomenon corresponds to the low YL peak in the PL spectrum of the fresh device. The YL intensity in the fresh device is nonzero because not all defects were passivated by H during growth. Thirdly,the dehydrogenation process has been observed in other nitride-based devices, and electrical stress will enhance this process.[43–45]Under high injection current,the junction temperature rises evidently,resulting in sufficient energy for carriers to transfer to the lattice, and the dehydrogenation process is prone to occur.[45,46]Therefore, the dehydrogenation of the previously passivated VGaand oxygen related complex defects after stress is likely to result in the activation of the VGarelated defects(e.g.,VGa–ON)and then induce the device degradation.

    4. Conclusions

    In summary,we have investigated the degradation mechanism of GaN-based NUV LEDs under electrical stress from the defect point of view. The optical power decreases,and the leakage current increases evidently after stress, which results from the increase in the concentration of defects with the energy level of 0.47–0.56 eV accompanied by the decrease of defects with the energy level of 0.72–0.84 eV.Combining the activation energy,the logarithmic relationship between DLTS signal and filling pulse width,with the increase of YL peak in PL spectrum during stress,the defects with increasing concentration can be attributed to VGaand oxygen related complex along dislocation. This defect may act as the non-radiative recombination center and parasitic leakage path, leading to device degradation.The defects with decreased concentration after stress can be ascribed to VGarelated defects that were passivated by H inherent during growth. During electrical stress,the dehydrogenation process around dislocations is likely to be the main origin for the degradation of GaN-based NUV LEDs.Therefore,more attention should be paid to the dislocation and the unintentionally induced hydrogen during growth in NUV LEDs.

    Acknowledgements

    Project supported by the National Natural Science Foundation of China(Grant Nos.62104180,61974115,11690042,61634005,61974111,12035019,and 61904142),and the Fundamental Research Funds for the Central Universities (Grant No.XJS221106),and the Key Research and Development Program of Shaanxi,China(Grant No.2020ZDLGY03-05).

    猜你喜歡
    陳凱雪峰
    要退休了
    雜文月刊(2019年19期)2019-12-04 07:48:34
    種七彩顏色的太陽
    這就是我
    清朝花瓶
    離婚,婚姻的一次“手術(shù)”
    女子世界(2017年6期)2017-06-08 20:16:15
    陳凱……
    看山是山?看山非山?
    雪峰下的草場
    中國三峽(2016年5期)2017-01-15 13:58:43
    王雪峰國畫
    歌海(2016年1期)2016-03-28 10:08:55
    開創(chuàng)新工藝 服務(wù)新標準——專訪同元祥總經(jīng)理陳凱
    專用汽車(2016年9期)2016-03-01 04:17:01
    久久久国产欧美日韩av| www.熟女人妻精品国产| 免费看不卡的av| 少妇 在线观看| 春色校园在线视频观看| 免费不卡的大黄色大毛片视频在线观看| 最新中文字幕久久久久| 欧美人与性动交α欧美精品济南到 | 精品国产超薄肉色丝袜足j| 欧美精品亚洲一区二区| 国语对白做爰xxxⅹ性视频网站| 激情五月婷婷亚洲| 国产男女内射视频| 亚洲熟女精品中文字幕| 国产黄色免费在线视频| 成人亚洲精品一区在线观看| 国产乱人偷精品视频| 少妇的丰满在线观看| 中文字幕人妻丝袜一区二区 | 亚洲欧美一区二区三区国产| 国产精品熟女久久久久浪| 99久久综合免费| 精品卡一卡二卡四卡免费| 夜夜骑夜夜射夜夜干| 高清欧美精品videossex| www日本在线高清视频| 国产 精品1| 韩国高清视频一区二区三区| 久久久久久人妻| 天天影视国产精品| 免费看不卡的av| 九草在线视频观看| 五月开心婷婷网| 男女下面插进去视频免费观看| 国产极品天堂在线| 在线观看国产h片| 丝袜脚勾引网站| 亚洲欧美色中文字幕在线| 免费高清在线观看日韩| 日本wwww免费看| 久久青草综合色| 国产无遮挡羞羞视频在线观看| 日本欧美视频一区| 麻豆av在线久日| 高清av免费在线| 又黄又粗又硬又大视频| 日韩视频在线欧美| 免费观看av网站的网址| 2018国产大陆天天弄谢| 999久久久国产精品视频| 国产爽快片一区二区三区| 天天躁狠狠躁夜夜躁狠狠躁| 久久久精品免费免费高清| 欧美精品高潮呻吟av久久| 一级黄片播放器| 国产黄色视频一区二区在线观看| 国产一区亚洲一区在线观看| 丝袜人妻中文字幕| 男人操女人黄网站| 26uuu在线亚洲综合色| 国产福利在线免费观看视频| 99re6热这里在线精品视频| a级片在线免费高清观看视频| 欧美精品高潮呻吟av久久| 日韩精品免费视频一区二区三区| 精品亚洲成a人片在线观看| 麻豆乱淫一区二区| 晚上一个人看的免费电影| 999久久久国产精品视频| 少妇的逼水好多| 99国产综合亚洲精品| 黑丝袜美女国产一区| 岛国毛片在线播放| kizo精华| 黄片小视频在线播放| 精品人妻熟女毛片av久久网站| 久久亚洲国产成人精品v| 中文字幕人妻丝袜一区二区 | 日韩电影二区| 国产毛片在线视频| 国产av精品麻豆| 日产精品乱码卡一卡2卡三| 亚洲国产av影院在线观看| av一本久久久久| 狂野欧美激情性bbbbbb| 极品少妇高潮喷水抽搐| 国产av一区二区精品久久| 亚洲精品美女久久av网站| 日本-黄色视频高清免费观看| 国产成人精品在线电影| 天堂中文最新版在线下载| 国产 一区精品| 亚洲一级一片aⅴ在线观看| 午夜久久久在线观看| 午夜福利视频精品| 国产日韩欧美在线精品| 伊人亚洲综合成人网| 国产精品 欧美亚洲| 亚洲欧美日韩另类电影网站| 亚洲精品美女久久av网站| 人人妻人人澡人人看| 99九九在线精品视频| 精品亚洲成a人片在线观看| 亚洲欧美精品自产自拍| 中文字幕色久视频| 丝袜脚勾引网站| 1024香蕉在线观看| 免费观看a级毛片全部| 我的亚洲天堂| 精品亚洲成国产av| 麻豆av在线久日| 青青草视频在线视频观看| 热re99久久精品国产66热6| 国产一区二区三区综合在线观看| 国产一区二区在线观看av| 一级毛片我不卡| 欧美成人精品欧美一级黄| 欧美国产精品va在线观看不卡| 欧美亚洲 丝袜 人妻 在线| 亚洲第一区二区三区不卡| 国产在线免费精品| 大香蕉久久网| 美女中出高潮动态图| 国产精品久久久久久精品古装| 欧美精品av麻豆av| 国产男人的电影天堂91| 亚洲国产欧美在线一区| 久久久久久久久久久久大奶| 亚洲在久久综合| 亚洲美女搞黄在线观看| 黑人欧美特级aaaaaa片| 亚洲成人av在线免费| 亚洲国产精品成人久久小说| 午夜久久久在线观看| 日本wwww免费看| av福利片在线| 日韩av免费高清视频| 热99国产精品久久久久久7| 久久精品国产亚洲av天美| 国产成人精品一,二区| 久久女婷五月综合色啪小说| 日韩av不卡免费在线播放| 久久精品人人爽人人爽视色| 国产福利在线免费观看视频| 美女脱内裤让男人舔精品视频| 亚洲,欧美精品.| 深夜精品福利| 高清视频免费观看一区二区| 亚洲欧美成人精品一区二区| 曰老女人黄片| 亚洲综合色网址| √禁漫天堂资源中文www| av在线观看视频网站免费| 国产精品 国内视频| 成年女人毛片免费观看观看9 | 超碰成人久久| 在线观看人妻少妇| 国产精品.久久久| 国产极品天堂在线| 高清av免费在线| 亚洲成国产人片在线观看| 汤姆久久久久久久影院中文字幕| 精品一品国产午夜福利视频| 欧美av亚洲av综合av国产av | 三级国产精品片| 麻豆乱淫一区二区| 久久精品国产亚洲av高清一级| 久久久久久久久久久免费av| 男人添女人高潮全过程视频| 久久精品国产亚洲av天美| 九色亚洲精品在线播放| 看免费av毛片| 日韩中文字幕视频在线看片| 亚洲精品久久久久久婷婷小说| 午夜福利,免费看| 99久久人妻综合| 卡戴珊不雅视频在线播放| 免费播放大片免费观看视频在线观看| 欧美激情高清一区二区三区 | 国产亚洲欧美精品永久| 男人操女人黄网站| 99久久中文字幕三级久久日本| 免费观看性生交大片5| 在线 av 中文字幕| 久久久a久久爽久久v久久| 午夜福利在线免费观看网站| 日本av免费视频播放| 国产av国产精品国产| 999精品在线视频| 国产午夜精品一二区理论片| 国产成人精品久久久久久| 少妇被粗大猛烈的视频| 亚洲熟女精品中文字幕| 日本wwww免费看| 丰满乱子伦码专区| 色吧在线观看| 亚洲av成人精品一二三区| 成人黄色视频免费在线看| 久久99蜜桃精品久久| 亚洲国产精品一区二区三区在线| 久久久久久久久久久免费av| 免费少妇av软件| 国产有黄有色有爽视频| 亚洲av国产av综合av卡| 大话2 男鬼变身卡| 这个男人来自地球电影免费观看 | 国产人伦9x9x在线观看 | 男女免费视频国产| 2018国产大陆天天弄谢| 国产精品免费视频内射| 日韩在线高清观看一区二区三区| av网站免费在线观看视频| 成人手机av| 亚洲av男天堂| 午夜老司机福利剧场| 国产亚洲最大av| 日本猛色少妇xxxxx猛交久久| 欧美少妇被猛烈插入视频| 国产精品熟女久久久久浪| 人妻少妇偷人精品九色| 建设人人有责人人尽责人人享有的| 久久热在线av| 色吧在线观看| 国产麻豆69| 亚洲av.av天堂| 日本vs欧美在线观看视频| 欧美日韩国产mv在线观看视频| 精品人妻一区二区三区麻豆| 女人高潮潮喷娇喘18禁视频| 亚洲国产看品久久| 香蕉丝袜av| 亚洲美女视频黄频| 精品国产国语对白av| 免费黄频网站在线观看国产| 亚洲一码二码三码区别大吗| 男人操女人黄网站| 各种免费的搞黄视频| 国产精品女同一区二区软件| 中文字幕av电影在线播放| 在线 av 中文字幕| 黄色 视频免费看| 国产色婷婷99| 亚洲在久久综合| 欧美人与善性xxx| 日韩欧美一区视频在线观看| 国产不卡av网站在线观看| 看十八女毛片水多多多| 女性生殖器流出的白浆| 亚洲av欧美aⅴ国产| av网站在线播放免费| 亚洲,一卡二卡三卡| 亚洲国产欧美日韩在线播放| 国产午夜精品一二区理论片| 人体艺术视频欧美日本| 亚洲成国产人片在线观看| 高清欧美精品videossex| 日日啪夜夜爽| 免费高清在线观看日韩| 欧美日韩亚洲高清精品| 国产日韩欧美在线精品| 免费在线观看完整版高清| 亚洲av日韩在线播放| 亚洲av电影在线进入| 交换朋友夫妻互换小说| 多毛熟女@视频| 激情视频va一区二区三区| 亚洲在久久综合| 99香蕉大伊视频| 亚洲欧美一区二区三区久久| 成年女人在线观看亚洲视频| 精品国产乱码久久久久久男人| 女性生殖器流出的白浆| 亚洲中文av在线| 亚洲成人av在线免费| 亚洲,欧美,日韩| 久久精品国产a三级三级三级| 97在线人人人人妻| 午夜日本视频在线| 国产av国产精品国产| 天天躁狠狠躁夜夜躁狠狠躁| 一级片免费观看大全| 啦啦啦在线免费观看视频4| tube8黄色片| 欧美+日韩+精品| 各种免费的搞黄视频| 建设人人有责人人尽责人人享有的| 亚洲久久久国产精品| 亚洲欧洲国产日韩| 一级毛片我不卡| 国产免费又黄又爽又色| 99国产综合亚洲精品| 欧美亚洲 丝袜 人妻 在线| 各种免费的搞黄视频| 卡戴珊不雅视频在线播放| 最近的中文字幕免费完整| 人人妻人人爽人人添夜夜欢视频| 欧美精品一区二区大全| 亚洲av男天堂| 女性被躁到高潮视频| 国产av一区二区精品久久| freevideosex欧美| 久久影院123| 天天躁夜夜躁狠狠躁躁| 波野结衣二区三区在线| 汤姆久久久久久久影院中文字幕| 亚洲熟女精品中文字幕| 国产1区2区3区精品| av国产精品久久久久影院| 老汉色∧v一级毛片| 国产一区二区三区综合在线观看| 亚洲精品美女久久久久99蜜臀 | 视频区图区小说| 国产片内射在线| 久久韩国三级中文字幕| 亚洲国产最新在线播放| 97人妻天天添夜夜摸| 精品国产超薄肉色丝袜足j| 国产一区二区激情短视频 | 永久免费av网站大全| 国产精品三级大全| 亚洲成人一二三区av| 国产免费现黄频在线看| 日本猛色少妇xxxxx猛交久久| 国产 精品1| 欧美日本中文国产一区发布| 一本色道久久久久久精品综合| 韩国高清视频一区二区三区| 老司机影院毛片| 欧美精品国产亚洲| 下体分泌物呈黄色| 18+在线观看网站| 国语对白做爰xxxⅹ性视频网站| 欧美av亚洲av综合av国产av | 免费日韩欧美在线观看| 考比视频在线观看| 久久久久精品久久久久真实原创| 久久国内精品自在自线图片| 久久久久久久亚洲中文字幕| 女人久久www免费人成看片| 精品国产一区二区久久| 亚洲欧美中文字幕日韩二区| 欧美精品高潮呻吟av久久| 26uuu在线亚洲综合色| 久久久久国产精品人妻一区二区| 日本黄色日本黄色录像| 十分钟在线观看高清视频www| 一级黄片播放器| 国产av精品麻豆| 观看美女的网站| 亚洲人成网站在线观看播放| 少妇被粗大猛烈的视频| 亚洲四区av| 国产一区有黄有色的免费视频| 久久99蜜桃精品久久| 中文乱码字字幕精品一区二区三区| 深夜精品福利| 国产精品亚洲av一区麻豆 | 免费黄色在线免费观看| 欧美+日韩+精品| 国产成人精品婷婷| 一边摸一边做爽爽视频免费| 深夜精品福利| 精品午夜福利在线看| 韩国高清视频一区二区三区| 熟女av电影| 18禁裸乳无遮挡动漫免费视频| 精品少妇久久久久久888优播| 老汉色∧v一级毛片| 亚洲久久久国产精品| 桃花免费在线播放| 日韩一区二区视频免费看| 中文字幕人妻丝袜一区二区 | 成年女人毛片免费观看观看9 | 亚洲,欧美,日韩| 亚洲精品aⅴ在线观看| 亚洲国产精品一区三区| 亚洲美女搞黄在线观看| 亚洲第一区二区三区不卡| 免费久久久久久久精品成人欧美视频| 精品国产超薄肉色丝袜足j| 亚洲人成77777在线视频| 国产成人av激情在线播放| 成年女人在线观看亚洲视频| 精品国产乱码久久久久久小说| 老司机影院成人| 亚洲男人天堂网一区| 多毛熟女@视频| 国产野战对白在线观看| 国产成人精品无人区| 午夜免费鲁丝| 亚洲人成网站在线观看播放| 精品国产乱码久久久久久小说| 国产一区二区 视频在线| 久久久精品免费免费高清| 国产极品粉嫩免费观看在线| 午夜激情av网站| 欧美+日韩+精品| 免费久久久久久久精品成人欧美视频| 999久久久国产精品视频| 欧美精品一区二区大全| 黄色毛片三级朝国网站| 国产淫语在线视频| 久久久精品国产亚洲av高清涩受| 老司机影院成人| 日本黄色日本黄色录像| 国产精品一区二区在线不卡| 秋霞伦理黄片| 桃花免费在线播放| 久久国内精品自在自线图片| 久热这里只有精品99| 亚洲成国产人片在线观看| 韩国av在线不卡| 大陆偷拍与自拍| 久久青草综合色| 18+在线观看网站| 日韩av免费高清视频| 丝袜喷水一区| 成人黄色视频免费在线看| 国产片特级美女逼逼视频| 成人亚洲精品一区在线观看| 黑人欧美特级aaaaaa片| 午夜精品国产一区二区电影| 91aial.com中文字幕在线观看| a 毛片基地| 黄频高清免费视频| 国产免费一区二区三区四区乱码| 国产不卡av网站在线观看| 亚洲天堂av无毛| 少妇人妻精品综合一区二区| 你懂的网址亚洲精品在线观看| 成人漫画全彩无遮挡| 亚洲国产欧美日韩在线播放| 两性夫妻黄色片| a 毛片基地| 大话2 男鬼变身卡| 最近手机中文字幕大全| 捣出白浆h1v1| 久久影院123| 成人午夜精彩视频在线观看| 1024视频免费在线观看| 丝袜脚勾引网站| 成年美女黄网站色视频大全免费| 亚洲精品av麻豆狂野| 精品亚洲成国产av| 成人国语在线视频| 91在线精品国自产拍蜜月| 18禁观看日本| 精品国产乱码久久久久久小说| 国产精品免费视频内射| 人成视频在线观看免费观看| 亚洲国产欧美网| 亚洲人成77777在线视频| 午夜免费鲁丝| av视频免费观看在线观看| 国产激情久久老熟女| 国产日韩欧美在线精品| 久久久精品国产亚洲av高清涩受| 另类精品久久| 免费人妻精品一区二区三区视频| 91精品伊人久久大香线蕉| 国产伦理片在线播放av一区| 日韩av免费高清视频| 一级爰片在线观看| 99热国产这里只有精品6| 国产乱来视频区| 男女啪啪激烈高潮av片| 日本欧美国产在线视频| 亚洲久久久国产精品| 一级片'在线观看视频| 波多野结衣av一区二区av| 日韩大片免费观看网站| 国产野战对白在线观看| 亚洲国产av影院在线观看| 欧美 日韩 精品 国产| 母亲3免费完整高清在线观看 | 日韩电影二区| 精品久久久久久电影网| 国产精品久久久久久久久免| a级毛片在线看网站| 九色亚洲精品在线播放| 欧美精品一区二区大全| 午夜老司机福利剧场| 日本免费在线观看一区| 丝袜美足系列| 色网站视频免费| 国产精品久久久久久av不卡| 午夜福利,免费看| 久久久久人妻精品一区果冻| 成年动漫av网址| 国产亚洲最大av| 国产色婷婷99| 国产成人精品婷婷| 亚洲av在线观看美女高潮| 美女主播在线视频| 国产精品久久久久久久久免| 如日韩欧美国产精品一区二区三区| 最近的中文字幕免费完整| 人体艺术视频欧美日本| 丝袜美足系列| 精品国产露脸久久av麻豆| av不卡在线播放| 久久精品国产亚洲av高清一级| av电影中文网址| 色94色欧美一区二区| 咕卡用的链子| 色网站视频免费| 亚洲欧美清纯卡通| 人人妻人人澡人人爽人人夜夜| 午夜福利视频精品| 国产一区二区激情短视频 | 精品国产超薄肉色丝袜足j| 久久99精品国语久久久| 建设人人有责人人尽责人人享有的| 日韩一本色道免费dvd| 在线免费观看不下载黄p国产| 永久网站在线| 热re99久久国产66热| 在线天堂最新版资源| av电影中文网址| 精品国产露脸久久av麻豆| 女性被躁到高潮视频| 麻豆av在线久日| 秋霞在线观看毛片| av在线观看视频网站免费| 国产精品99久久99久久久不卡 | 久久精品国产自在天天线| 九九爱精品视频在线观看| 国产精品 国内视频| 欧美国产精品va在线观看不卡| 久久精品国产亚洲av涩爱| 国产精品三级大全| 少妇精品久久久久久久| 久久这里只有精品19| 精品国产超薄肉色丝袜足j| 99香蕉大伊视频| 老女人水多毛片| 亚洲国产av影院在线观看| 国产日韩欧美在线精品| 又大又黄又爽视频免费| 国产精品麻豆人妻色哟哟久久| 中国三级夫妇交换| 老女人水多毛片| 99香蕉大伊视频| 熟妇人妻不卡中文字幕| 性少妇av在线| 久久久久久久国产电影| 亚洲av成人精品一二三区| 精品人妻一区二区三区麻豆| 日韩制服骚丝袜av| 久久久久久人妻| 最近最新中文字幕免费大全7| 老熟女久久久| 免费不卡的大黄色大毛片视频在线观看| 国产一区有黄有色的免费视频| av网站在线播放免费| 少妇的逼水好多| 久久99热这里只频精品6学生| 在线天堂最新版资源| 妹子高潮喷水视频| xxx大片免费视频| 九草在线视频观看| a级毛片黄视频| av福利片在线| 欧美变态另类bdsm刘玥| av卡一久久| 久久久亚洲精品成人影院| 男人舔女人的私密视频| 国产激情久久老熟女| 久久女婷五月综合色啪小说| 麻豆精品久久久久久蜜桃| 亚洲综合色惰| 亚洲,欧美精品.| 国产精品熟女久久久久浪| 免费在线观看黄色视频的| 国产午夜精品一二区理论片| 亚洲成人手机| 超色免费av| 日本欧美视频一区| 少妇猛男粗大的猛烈进出视频| 成人毛片60女人毛片免费| 婷婷成人精品国产| 国产男女内射视频| 国产免费现黄频在线看| 建设人人有责人人尽责人人享有的| 亚洲av.av天堂| 亚洲,欧美精品.| 女性被躁到高潮视频| 亚洲欧美成人综合另类久久久| 国产av一区二区精品久久| 国产在视频线精品| 婷婷色综合大香蕉| 久久精品熟女亚洲av麻豆精品| 啦啦啦视频在线资源免费观看| 人成视频在线观看免费观看| 亚洲精品一区蜜桃| 青青草视频在线视频观看| 亚洲欧美精品自产自拍| 国产精品久久久久久久久免| 2018国产大陆天天弄谢| 欧美日韩综合久久久久久| 亚洲精品成人av观看孕妇| 色婷婷av一区二区三区视频| 亚洲在久久综合| 国产老妇伦熟女老妇高清| 欧美日韩一级在线毛片| 久久毛片免费看一区二区三区| 日韩欧美精品免费久久| 久久精品亚洲av国产电影网| 亚洲第一av免费看| 最近中文字幕高清免费大全6| 天天操日日干夜夜撸| 涩涩av久久男人的天堂| 啦啦啦中文免费视频观看日本| 男的添女的下面高潮视频| av线在线观看网站|