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摘要: 利用GaN光电阴极多信息量测试评估系统，对反射式梯度掺杂和均匀掺杂GaN光电阴极样品进行了激活及衰减后的量子效率测试，并测试衰减速率。在同样的衰减时间内，和均匀掺杂样品相比，梯度掺杂样品的衰减比例较小，衰减速率较慢，其原因在于梯度掺杂结构可在其发射层内部产生系列内建电场，致使其能带连续向下弯曲，导致其表面真空能级比均匀掺杂样品下降得更低，发射层表面形成的负电子亲和势更明显，造成发射层内的光生电子更易逸出，阴极量子效率的衰减变慢，从而使其稳定性强于均匀掺杂结构。Abstract: The GaN photocathode multi-information measurement and evaluation system is used to test the quantum efficiency of the reflective gradient-doped and uniformly doped GaN photocathode samples after activation and attenuation, and the attenuation rate test is performed. The gradient-doped sample has a smaller attenuation ratio and a slower decay rate than the uniform-doped sample within the same decay time because the gradient-doped structure can generate a series of built-in electric fields inside the emissive layer. As a result, the energy band can be continuously bent downwards, resulting in a lower surface vacuum level than that of the uniformly doped sample, and the negative electron affinity formed on the surface of the emission layer is more pronounced, resulting in easier escape of photogenerated electrons in the emission layer. The decay of the cathode quantum efficiency becomes slower, making it more stable than uniform-doped structures.
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Key words:
- GaN /
- photocathode /
- gradient-doping /
- built-in electric field /
- stability
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图 1 反射式均匀掺杂样品A和梯度掺杂样品B结构图
Figure 1. Structure of reflection-mode uniform-doping sample A and gradient-doping sample B
图 2 样品A和B在激活结束后的量子效率测试曲线
Figure 2. Quantum efficiency curves of sample A and sample B after activation
图 3 样品A和B的量子效率测试曲线
Figure 3. Quantum efficiency curves of GaN photocathodes in variable conditions
图 5 反射式GaN光电阴极的表面势垒示意图
Figure 5. Surface potential barrier of reflection-mode GaN photocathode
图 6 均匀掺杂样品A和梯度掺杂样品B能带结构示意图(Ec为导带能级，Ev为价带能级，EF为费米能级，E0为真空能级，Eg为GaN的禁带宽度)
Figure 6. Energy band structure of uniform-doping sample A and gradient-doping sample B(EC is the conduction band minimum, EV is the valence band maximum, EF is the Fermi level, E0 is the vacuum level, Eg is the band gap)
表 1 均匀掺杂样品A的衰减测试结果
Table 1. Quantum efficiency attenuation test results of sample A
波长/nm 240 260 280 300 320 340 激活后QE/% 51 36 27 20 16 14 12 h后QE/% 42 25 16 9.8 6.2 4.9 衰减比例/% 17.6 30.6 40.7 46 61.2 65 注：衰减比例为(激活后QE-12 h后QE)/激活后QE。 
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表 2 梯度掺杂样品B的衰减测试结果
Table 2. Quantum efficiency attenation test results of sample B
波长/nm 240 260 280 300 320 340 激活后QE/% 57 44 36 28 24 21 12 h后QE/% 48 32 24 18 13 10 衰减比例/% 15.8 27.3 33.3 35.7 45.8 52.4 注：衰减比例为(激活后QE-12 h后QE)/激活后QE。
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表 3 样品A和样品B的衰减速率测试结果
Table 3. Attenuation rate test results of decadence rate for uniform-doping sample A and gradient-doping sample B
衰减速率(a.u/h) 测试时间/h 2 4 6 8 10 12 梯度掺杂样品B 32 19.1 12.7 10.4 4.7 4.6 均匀掺杂样品A 40 30 19.1 17.6 14.3 8.3 注：衰减速率为(测试值1-测试值2)×100/测试值1。
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[1] 洪国彬, 杨钧杰, 卢廷昌.蓝紫光氮化镓光子晶体面射型激光器[J].中国光学, 2014, 7(4):559-571. http://www.chineseoptics.net.cn/CN/abstract/abstract9184.shtmlHONG K B, YANG CH CH, LU T CH. Blue-violet GaN-based photonic crystal surface emitting lasers[J]. Chin. Opt., 2014, 7(4):559-571.(in Chinese) http://www.chineseoptics.net.cn/CN/abstract/abstract9184.shtml [2] 秦华, 黄永丹, 孙建东, 等.二维电子气等离激元太赫兹波器件[J].中国光学, 2017, 10(1):51-67. http://www.chineseoptics.net.cn/CN/abstract/abstract9511.shtmlQIN H, HUANG Y D, SUN J D, et al.. Terahertz-wave devices based on plasmons in two-dimensional electron gas[J]. Chin. Opt., 2017, 10(1):51-67.(in Chinese) http://www.chineseoptics.net.cn/CN/abstract/abstract9511.shtml [3] 蔡丽娥, 张保平, 张江勇, 等.GaN基蓝光VCSEL的制备及光学特性[J].发光学报, 2016, 37(4):452-456. http://www.cqvip.com/QK/92489X/201604/668520133.htmlCAI L E, ZHANG B P, ZHANG J Y, et al.. Fabrication and characteristics of GaN-based blue VCSEL[J]. Chinese J. Luminescence, 2016, 37(4):452-456.(in Chinese) http://www.cqvip.com/QK/92489X/201604/668520133.html [4] 邹水平, 吴柏禧, 万珍平, 等.电-热应力对GaN基白光LED可靠性的影响[J].发光学报, 2016, 37(1):124-129. http://www.cqvip.com/QK/92489X/201601/667808202.htmlZOU SH P, WU B X, WAN ZH P, et al.. Effect of current-temperature stress on the reliability of GaN LED[J]. Chinese J. Luminescence, 2016, 37(1):124-129.(in Chinese) http://www.cqvip.com/QK/92489X/201601/667808202.html [5] 李志全, 王聪, 李文超, 等.利用Ag/P-GaN双光栅改善LED发光特性[J].光学 精密工程, 2017, 25(5):1185-1191. http://wuxizazhi.cnki.net/Sub/yqyb/a/GXJM201705009.htmlLI ZH Q, WANG C, LI W CH, et al.. Improving LED luminescence properties by using Ag/P-GaN double grating[J]. Opt. Precision Eng., 2017, 25(5):1185-1191.(in Chinese) http://wuxizazhi.cnki.net/Sub/yqyb/a/GXJM201705009.html [6] 王永进, 张锋华, 高绪敏, 等.面向可见光波段的非周期悬空GaN薄膜光栅[J].光学 精密工程, 2017, 25(12):3020-3026. https://www.wenkuxiazai.com/word/00576a9fd5bbfd0a795673eb-1.docWANG Y J, ZHANG F H, GAO X M, et al.. Freestanding non-periodic GaN gratings in visible wavelength region[J]. Opt. Precision Eng., 2017, 25(12):3020-3026.(in Chinese) https://www.wenkuxiazai.com/word/00576a9fd5bbfd0a795673eb-1.doc [7] SOMMER A H. Stability of photocathode[J]. Appl. Opt., 1973, 12(1):90-92. doi: 10.1364/AO.12.000090 [8] 徐江涛.真空残气对GaAs阴极发射性能的影响[J].应用光学, 2003, 24(2):13-15. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=yygx200302005XU J T. Effect of residual gas on emission property of Gallium Arsenide cathode in vacuum[J]. J. Appl. Opt., 2003, 24(2):13-15.(in Chinese) http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=yygx200302005 [9] WADA T, NITTA T, NOMURA T. Influence of exposure to CO, CO2 and H2O on the stability of GaAs photocathodes[J]. Jpn. J. Appl. Phys., 1990, 29(10):2087-2091. https://www.researchgate.net/profile/Shiyu_Sun4 [10] MACHUCA F. A Thin Film p-type GaN Photocathode: prospect for a high performance electron emitter[D]. Stanford: University Stanford, 2004. [11] ZOU J J, CHANG B K. Gradient-doping negative electron affinity GaAs photocathodes[J]. Opt. Eng., 2006, 45(5):054001. doi: 10.1117/1.2205171 [12] YANG ZH, CHANG B K, ZOU J J. Comparison between gradient-doping GaAs photocathode and uniform-doping GaAs photocathode[J]. Appl. Opt., 2007, 46(28):7035-7039. doi: 10.1364/AO.46.007035 [13] 乔建良, 常本康, 杜晓晴, 等.反射式负电子亲和势GaN光电阴极量子效率衰减机理研究[J].物理学报, 2010, 59(4):2855-2859. doi: 10.7498/aps.59.2855QIAO J L, CHANG B K, DU X Q, et al.. Quantum efficiency decay mechanism for reflection mode negative electron affinity GaN photocathode[J]. Acta Phys. Sinica, 2010, 59(4):2855-2859.(in Chinese) doi: 10.7498/aps.59.2855 [14] 高频, 王晓晖, 杜玉杰, 等.NEA GaN光电阴极的制备与评估[J].红外技术, 2011, 33(6):332-335. http://www.cqvip.com/QK/92901X/201106/38270750.htmlGAO P, WANG X H, DU Y J, et al.. Preparation and evaluation of NEA GaN photocthode[J]. Infrared Technol., 2011, 33(6):332-335.(in Chinese) http://www.cqvip.com/QK/92901X/201106/38270750.html [15] IWAYA M, TAKEUCHI T, YAMAGUCHI S, et al.. Reduction of etch pit density in organometallic vapor phase epitaxy-grown GaN on sapphire by insertion of a low-temperature-deposited buffer layer between high-temperature-grown GaN[J]. Jpn. J. Appl. Phys., 1998, 37:L316-L318. doi: 10.1143/JJAP.37.L316 [16] NAKCMURA S, MUKAI T, SENOH M, et al.. Thermal annealing effects on p-type Mg-doped GaN films[J]. Jpn. J. Appl. Phys., 1992, 31:L139-L140. doi: 10.1143/JJAP.31.L139 [17] MACHUCA F, LIU Z. Fabrication of group Ⅲ-Nitride photocathode having Cs activation layer: US, 0170324 A1[P]. 2006-01-01. [18] TERESHCHENKO O E, SHAIBLER G, YAROSHEVICH A S, et al.. Low-temperature method of cleaning p-GaN(0001) surfaces for photoemitters with effective negative electron affinity[J]. Phys. Solid State, 2004, 46(10):1949-1953. doi: 10.1134/1.1809437 [19] KING S W, BARNAK J P, BREMSER M D, et al.. Cleaning of AlN and GaN surfaces[J]. J. Appl. Phys., 1998, 84(9):5248-5260. doi: 10.1063/1.368814 [20] 乔建良, 田思, 常本康, 等.负电子亲和势GaN光电阴极激活机理研究[J].物理学报, 2009, 58(8):5847-5851. doi: 10.7498/aps.58.5847QIAO J L, TIAN S, CHANG B K, et al.. Activation mechanism of negative electron affinity GaN photocathode[J]. Acta Phys. Sinica, 2009, 58(8):5847-5851.(in Chinese) doi: 10.7498/aps.58.5847 [21] 邹继军, 常本康, 杜晓晴, 等.GaAs光电阴极光谱响应曲线形状的变化[J].光谱学与光谱分析, 2007, 27(8):1465-1468. http://www.cqvip.com/QK/90993X/200708/25252972.htmlZOU J J, CHANG B K, DU X Q, et al.. Variation of spectral response curve shape of GaAs photocathodes[J]. Spectrosc. Spectral Anal., 2007, 27(8):1465-1468.(in Chinese) http://www.cqvip.com/QK/90993X/200708/25252972.html [22] NIU J, ZHANG Y J, CHANG B K, et al.. Influence of varied doping structure on photoemissive property of photocathode[J]. Chin. Phys. B, 2011, 20(4):044209. doi: 10.1088/1674-1056/20/4/044209 [23] 张益军. 变掺杂GaAs光电阴极研制及其特性评估[D]. 南京: 南京理工大学, 2012. http://www.wanfangdata.com.cn/details/detail.do?_type=degree&id=Y2275823ZHANG Y J. Design and characteristic evaluation of varied doping GaAs photocathode[D]. Nanjing: Nanjing University of Science and Technology, 2012. (in Chinese) http://www.wanfangdata.com.cn/details/detail.do?_type=degree&id=Y2275823 -
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