固溶体半导体ZnMgS多晶薄膜的制备及其性能研究
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摘要
ZnS是一种重要的Ⅱ—Ⅵ族直接带隙半导体材料，室温下其禁带宽度为3.6eV，激子束缚能为40meV，在蓝紫光发光二极管和激光二极管等光电器件方面具有广阔的应用前景。通过引入Mg替代ZnS中的Zn所形成的固溶化合物ZnMgS，可以实现对发光波长、晶格常数和禁带宽度等不同变化的要求，这些特性对于半导体光电器件的设计和制作十分关键。因此对固溶体ZnMgS材料的研究具有非常重要的意义。
本文利用真空蒸镀法在石英玻璃和ITO玻璃等基底上成功制备了一系列含有不同Mg成分的Zn_(1-x)Mg_xS薄膜，借助于X射线能量色散谱(EDS)仪、原子力显微镜(AFM)、X射线衍射(XRD)仪、激光拉曼(Raman)光谱仪、紫外—可见(UV—Vis)分光光度计、光致发光(PL)光谱仪等测试手段对薄膜的成分、表面形貌、晶体结构以及光学性能等方面做了相关的测试，得出以下结论：
石英基底上，在所制备的成分范围(0≤x≤0.73)内，薄膜晶体生长形貌和结晶性良好，为闪锌矿结构；拉曼光谱的特征谱峰比较明显；薄膜在波长为356～275nm处形成陡峭的吸收边，在波长小于275nm的紫外区有强烈的吸收，得出薄膜的禁带宽度可以在3.6eV到4.1eV之间调节，结合维戈定律推出带隙的表达式：E_g(x)=0.6869x~2+0.2131x+3.6；光致发光谱中发光中心波长在可见光区蓝紫光范围约为420～395nm之间。随着Mg含量的增加，样品的X射线衍射(111)峰位向大角度方向移动；拉曼谱特征峰向高波数移动；吸收边和发光峰的蓝移也增加。蓝移说明了带隙的展宽，薄膜带隙可调并且保持了单晶的优良特性有利于作为短波光电器件和拓展紫外发光器件材料。
在ITO玻璃基底上沉积的ZnMgS薄膜初步呈现了良好的结晶性能和发光等光学性能。说明了关于ITO玻璃为基底的高质量的ZnMgS薄膜的研究对场发射平板显示器的实现有重要意义，也具有制作光致发光和电致发光器件良好的应用前景。
ZnS is a kind of important II-VI direct band-gap semiconductor materials(3.6eV at room temperature).it has comparatively large exciton binding energy of 40meV. ZnS is a kind of very promising materials for making the optoelectronics devices such as UV/blue light-emitting diodes and short-wavelength semiconductor diode laser devices being developed and put in application. The solid-solution ZnMgS can be formed by introducing Mg into ZnS and filling in it. It can have different luminescence wavelength, crystal lattice parameter and band gap. These characteristic are key to designing and making semiconductor optoelectronics devices. So it is all-important to research solid-solution semiconductor ZnMgS materials.
Solid solution polycrystalline Zn_(1-x)Mg_xS thin films were grown successfully on amorphous quartz glass and ITO glass substrates by vacuum evaporation and it has different content of Mg. The compositions, structures, morphologies and optical characterizations of the thin films were investigated by EDS, XRD, Raman, AFM, UV-visible absorption spectra and PL spectra and the results indicate that Zn_(1-x)Mg_xS thin films have uniformly morphology and show a (111) oriented zinc-blend structure. The films have very strong absorption in the short wavelength range and the absorption edge is about between 356 and 275nm.And deducting the expression of band-gap: E_g(x) =0.6869x~2+0.2131x+3.6. PL peaks locate between 420 nm and 395nm without other emission at room temperature. With increasing of Mg component, (111) peaks move a little to large angle, the absorption edge and PL peak are found blue shift obviously, which indicate band-gap becomes wide and it increases from 3.60ev to 4.1ev. According to these characterizations, it is concluded that Zn_(1-x)Mg_xS thin films are promising materials for short wavelength optoelectronic applications and ultraviolet detectors. The structures, morphologies, optical and electrical characterizations of the films prepared on ITO glass by investigating are all right. It shows important sense and considerable application foreground to carrying out field emission-flat display and photoluminescence and electroluminescence devices at the same time.
本文利用真空蒸镀法在石英玻璃和ITO玻璃等基底上成功制备了一系列含有不同Mg成分的Zn_(1-x)Mg_xS薄膜，借助于X射线能量色散谱(EDS)仪、原子力显微镜(AFM)、X射线衍射(XRD)仪、激光拉曼(Raman)光谱仪、紫外—可见(UV—Vis)分光光度计、光致发光(PL)光谱仪等测试手段对薄膜的成分、表面形貌、晶体结构以及光学性能等方面做了相关的测试，得出以下结论：
石英基底上，在所制备的成分范围(0≤x≤0.73)内，薄膜晶体生长形貌和结晶性良好，为闪锌矿结构；拉曼光谱的特征谱峰比较明显；薄膜在波长为356～275nm处形成陡峭的吸收边，在波长小于275nm的紫外区有强烈的吸收，得出薄膜的禁带宽度可以在3.6eV到4.1eV之间调节，结合维戈定律推出带隙的表达式：E_g(x)=0.6869x~2+0.2131x+3.6；光致发光谱中发光中心波长在可见光区蓝紫光范围约为420～395nm之间。随着Mg含量的增加，样品的X射线衍射(111)峰位向大角度方向移动；拉曼谱特征峰向高波数移动；吸收边和发光峰的蓝移也增加。蓝移说明了带隙的展宽，薄膜带隙可调并且保持了单晶的优良特性有利于作为短波光电器件和拓展紫外发光器件材料。
在ITO玻璃基底上沉积的ZnMgS薄膜初步呈现了良好的结晶性能和发光等光学性能。说明了关于ITO玻璃为基底的高质量的ZnMgS薄膜的研究对场发射平板显示器的实现有重要意义，也具有制作光致发光和电致发光器件良好的应用前景。
ZnS is a kind of important II-VI direct band-gap semiconductor materials(3.6eV at room temperature).it has comparatively large exciton binding energy of 40meV. ZnS is a kind of very promising materials for making the optoelectronics devices such as UV/blue light-emitting diodes and short-wavelength semiconductor diode laser devices being developed and put in application. The solid-solution ZnMgS can be formed by introducing Mg into ZnS and filling in it. It can have different luminescence wavelength, crystal lattice parameter and band gap. These characteristic are key to designing and making semiconductor optoelectronics devices. So it is all-important to research solid-solution semiconductor ZnMgS materials.
Solid solution polycrystalline Zn_(1-x)Mg_xS thin films were grown successfully on amorphous quartz glass and ITO glass substrates by vacuum evaporation and it has different content of Mg. The compositions, structures, morphologies and optical characterizations of the thin films were investigated by EDS, XRD, Raman, AFM, UV-visible absorption spectra and PL spectra and the results indicate that Zn_(1-x)Mg_xS thin films have uniformly morphology and show a (111) oriented zinc-blend structure. The films have very strong absorption in the short wavelength range and the absorption edge is about between 356 and 275nm.And deducting the expression of band-gap: E_g(x) =0.6869x~2+0.2131x+3.6. PL peaks locate between 420 nm and 395nm without other emission at room temperature. With increasing of Mg component, (111) peaks move a little to large angle, the absorption edge and PL peak are found blue shift obviously, which indicate band-gap becomes wide and it increases from 3.60ev to 4.1ev. According to these characterizations, it is concluded that Zn_(1-x)Mg_xS thin films are promising materials for short wavelength optoelectronic applications and ultraviolet detectors. The structures, morphologies, optical and electrical characterizations of the films prepared on ITO glass by investigating are all right. It shows important sense and considerable application foreground to carrying out field emission-flat display and photoluminescence and electroluminescence devices at the same time.
引文
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[2] M.A. Haase, J. Qiu, J. M. Depuydt, and H. Cheng, Blue-green laser diodes, Appl. phys. Lett., 1991,59(11):1272—1274
[3] E.symposium. Properties of Ⅱ—Ⅵ semiconductor: Bulk crystals, Epitaxial films, Quantum Well structures and dilute Magnetic systems, American Material.Research society, Nov.27-Dec.1,1989.
[4] R.Zimmermann, J.Crystal Growth101(1990)346.
[5] T.Taguchi, C.Onodera, Y.Yamada, Y.Masumoto, Band offsets in CdZnS/ZnS strained-layer quantum well and its application to laser diode. Jpn. J.Appl.Phys, 1993, 32, L1308-1311.
[6] W.Leigh, B.W.Wessels, High conductivity zinc sulphoselenide thin films Applied Physics Letters, (1982), 41(2), 165～167.
[7] S.Shionoya and W.M.Yen (Chaireditor.).Phosphor andbook; CR cpress; Boca, Raton, Boston, London, NewYork, Washington. D.C.1999:137-141
[8] 陈中钧，肖海燕，祖小涛．MgS晶体结构性质的密度泛函研究[J]物理学报2005／54(11)5301—07．
[9] Ryo Inoue, Masahiko Kitagawa, Takayoshi Nishigki, et al. Optical band gap of Zn_xMg_(1-x)S thin films with composition x between 0.14 and 1.0[J] Journal of Crystal Growth 184/185, 1998, 1076-1080.
[10] Hideaki Kimijima, Masahiko Kitagawa, Ryou Inoue, et al. Deposition and characterization of Zn_xMg_(1-x)S thin films on amorphous substrates[J].Applied Surface Science113/114, 1997, 432—435.
[11] K.Akimoto, H.okuyama, M.Ikeda, Y.Mori, Iso electronic oxygen in Ⅱ—Ⅵ semiconductors[J]. Appl. phys. lett 1992,1:91-93.
[12] 孙涛，黄锦圣，张伟力等．ZnSSe双光子吸收光电二极管的自相关器[J]光学学报2003．2
[13] A.Mikami,1997 SID Int. Symp., Digest of Technical Papers,SID, Boston,1997,p.34.
[14] I.K.Sou, Marcus C.W.Wu, T.Sun, et al. Molecular-beam-epitaxy-grown ZnMgS ultraviolet photodetectors[J]. Appl. phys. Lett.2001,VOLUME78, NUMBER13
[15] L.W.Lu, I.K.Sou, W.K.Ge Influence of Mg content on molecular-beam-epitaxy-grown ZnMgS ultraviolet photodetectors[J]. Journal of Crystal Growth 265 (2004) 28-33. )
[16] H.Okuyama, K.Nakano, T.Miyajima, K.Akimoto, Jpn. J.Appl,Phys.30(1991)L1620.
[17] K.Ichino, H.Kariya, N.Suzuki, et al.Molecular beam epitaxy and optical properties of ZnCdS/ZnMgS quantum wells on GaP[J]. Journal of Crystal Growth,214/215,2000, 135-139.
[18] T.Tawara, I.Suemune, S.Tanaka. MOVPE growth of ZnSe/ZnMgS distributed Bragg reflectors with high refractive-index contrast[J]. Journal of Crystal Growth, 2000, 214/215 (1019-1023.)
[19] V.Sallet, A.Lusson, M.Rommeluere, et al. MOCVD growth and characterization of ZnS and Znl_xMg_xS alloys[J]. Journal of Crystal Growth,2000,220:209-215.
[20] K.A.Prior, S.A.Telfer, X.Tang, et al. Growth of (Zn,Cd)S and (Zn,Mg)S containing structures on GaP[J]. Journal of Crystal Growth,227-228(2001)655-659,
[21] 冯端主编．金属物理．
[22] Ohtomo A, Kawasaki M, Koida T, et al.ZnMgO as a wide gap semiconductor alloy[J]. Apply phys lett, 1998, 72:2466.
[23] Ryo Inoue, Masahiko Kitagawa, Takayoshi Nishigki, et al. Growth and luminescence of Zn_xMg_(1-x)S:Mn ternary compound crystal films[J] Journal of Crystal Growth, 198/199 (1999) 1196—1204.
[24] 陆家和，陈长彦．现代分析技术，清华大学出版社，1995年9月第一版：26，110—180)
[25] 丛秋滋．多晶二维X射线衍射．科学出版社．1997．p36
[26] 黄昆，韩汝琦．固体物理学，第九章，P437，高等教育出版社
[27] Pankove J I. Optical Processes in Semiconductors, Princeton Publ,1973
[28] Greenaway D L and Harbeke G. Optical Properties and Band Structure of Semiconductors. Pergamon Press, 1968
[29] Seraphin B O. Optical Properties of Solids—New Developments. North Holland,1976
[30] Seeger K著．徐乐，钱建业译．半导体物理．人民教育出版社，1980
[31] 金原桑(日)著，杨希光泽，薄膜的基本技术[M]．北京：科学出版社，1982
[32] 张以忱．真空工艺[J]．真空，2003(2)：63—66．
[33] 李远、周志刚、秦自楷等编著，压电与铁电材料的测量，科学出版社，1984年9月第一版
[34] Y.Yamada, T.Mishima, Y.Matsomoto, et al, Time resolved nonlinear luminescence of biexcitions in ZnSe-ZnMgSSe single quantum well,Phys.Rev.B,1995,52:2289—2295
[35] Ryo Inoue, Masahiko Kitagawa, Takayoshi Nishigki, et al. Optical band gap of Zn_xMg_(1-x)S thin films with composition x between 0.14 and 1.0[J] Journal of Crystal Growth, 1998, 185:1076-1080.
[36] 陈国平 主编，薄膜物理与技术，东南大学出版社．
[37] 陈治明，王建农，半导体器件的材料物理学基础，第五章，p263，科学出版社．
[38] W.T.Lim, C.H.Lee, Thin solid films 353,12(1999).
[39] Yang Chuanzheng. Progress in Physics[J],1999,19(2): 183—216.
[40] 韩建成 多晶X射线结构分析，华东师范大学出版社，1989年9月第一版：26，110—180
[41] Li Xue Dan. Technology of Vacuum Deposition[M]. Hangzhou: Publishing House of Zhejiang University,1994,239
[42] W.Shan, W.Walukiewicz, J.W.A.LLL, K.M.Yu, J.Wu, E.E.Haller, Y.Nabetani, T.Mukawa, Y.lto, T.Matsumoto,Appl.Phys.LETT.83(2003)299
[43] 吴小昆，杨宇，吴兴惠．Raman测量Ge/Sj多层膜中晶粒尺寸的理论研究[J]．红外技术，2001，23(1)：15
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