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题名	硫系非晶半导体薄膜的光致性能变化的研究
作者	刘启明
学位类别	博士
答辩日期	2002
授予单位	中国科学院上海光学精密机械研究所
导师	干福熹
关键词	硫系非晶半导体薄膜 光致暗化 光致漂白 光致结晶 OHD-OKE及三阶光学非线性
其他题名	Photoinduced Changes of Properties in Amorphous Chalcogenide Semiconductor Films
中文摘要	硫系非晶半导体薄膜在光的作用下会出现许多现象，如光致暗化，光致漂白，光致结晶，光掺杂，光致二阶非线性现象等，导致这些现象产生的原因可能是光致结构变化所致。硫系非晶半导体薄膜中所出现的一些光致效应已成功应用于现代微电子和光电子领域的各个方面。近年来，人们对一些硫系玻璃半导体中的光致效应虽已研究较多，但对其产生机理至今仍不是十分清楚。此夕卜由于硫系非晶半导体薄膜的折射率较高，研究其非线性光学性质，对探索新型非线性光学材料，满足光电子器件发展的需要，也具有重要的意义。本文系统地研究了As2S3，As2Se3，GeS2，GeSe2，Ge20As25S55，Ge20As25Se55，Ge10As40S20Se30七个体系硫系非晶半导体薄膜与光相互作用中所出现的光致暗化，光致漂白，光致结晶效应，并且首次利用飞秒超外差光克尔效应法（OHD-OKE）测出了薄膜的三阶非线性极化率X（3）的实部、虚部值及其符号和非线性响应时间。经过514.5nm的氢离子激光辐照或退火处理后，在As2S3，As2Se3和Ge10As40S20Se30三个体系的硫系非晶半导体薄膜中观察到光致暗化效应，光学吸收边发生红移，并且红移的大小是随着辐照激光功率的增大和光照时间的延长而增加的，并最后达到饱和。光致光学吸收边的红移分为可逆和不可逆两个过程，在预先退火处理的薄膜中是可逆的，即通过再退火光学吸收边可以恢复到原来的位置。硫系非晶半导体薄膜的光致暗化效应的发生与薄膜的光致结构变化有关，利用这种光致暗化效应的可逆性可以设计出新型的光存储材料。经过514.5nm的氢离子激光辐照或退火处理后，在GeS2，GeSe2，Ge20As25S55，Ge20AS25se55，四个体系硫系非晶半导体薄膜中，观察到光学吸收边发生绿移，即发生了光致漂白效应，这是与光致暗化效应相反的一种效应。其中，光学吸收边绿移值的大小也是随着辐照激光功率的增大和光照时间的延长而增加的，并最后达到饱和。硫系非晶半导体薄膜中光致漂白效应的发生是由于光致结构变化所致，包括可逆和不可逆两个过程，在先退火处理的薄膜中是可逆的，即进行再退火光学吸收边可以恢复到原来的位置，利用这种可逆性也可以设计出新型的光存储材料。硫系非晶半导体薄膜光照后出现光致暗化和光致漂白效应，是由于光致结构变化所致。进一步的扫描电镜和透射电镜测试表明，薄膜在光照后，表面有颗粒物析出，电子衍射表明该析出颗粒为晶相，而未光照的薄膜为非晶相，说明薄膜经激光辐照后发生了光致结晶效应。超外差光克尔效应法（OHD-OKE）是在普通的光克尔效应法（OKE）的基础上，近年来发展起来的一种比较先进的测量材料三阶非线性极化率了3）的方法。本文首次使用飞秒OHD-OKE法测出了硫系非晶半导体薄膜的三阶非线性极化率了X(3）的实部、虚部值及其符号和非线性响应时间。结果表明，硫系非晶半导体薄膜具有较大的三阶非线性极化率丫3），尤其是非线性响应时间非常快，将是光电子器件发展的一种很好的非线性光学材料。
英文摘要	Amorphous chalcogenide films are known to exhibit several photoinduced phenomina, such as photodarkening, photobleaching, photocrystallization, photodoping, and photoinduced second-order nonlinearity so on, which are connected with photoinduced structural transformations. Some phenomina have already been applied in various fields of modern microelectronics and electrooptics. Although the photoinduced effects in amorphous semiconductors have been studied for the past decade years, the complete knowledge of the mechanism of the process has not been obtained yet. It is also important for the need of the development of optoelectronic devices to study the optical nonlinearities of amorphous chalcogenide semiconductor films because their refractive indexes are high. In this dissertation, the photodarkening, photobleaching, photocrystallization were systematically studied on the As2S3, As2Se3, GeS2, GeSe2, Ge20As25S55, Ge20As25Se55, Ge|OAs4OS2OSe3O systems. By the method of femtosecond optical heterodyned detection of optical Kerr effect (OHD-OKE), the values and the signs of both the real and the imaginary parts of %(3) and the response time of amorphous chalcogenide semiconductor films were firstly obtained. Illuminated by an argon ion laser at 514.5 nm or annealed near the glass-transition temperature, photodarkening was observed in the As2S3, As2Se3 and Ge10As40S2OSe30 amorphous chalcogenide semiconductor films and the optical absorption edges were red-shift. The magnitude of shift increased with the increase of the intensity of illumination light and the illumination time and became saturated finally. The red-shift of optical absorption edge includes reversible and irreversible processes. It is reversible in well-annealed films and the red-shift can be recovered by annealing the films again. The photodarkening in the As2S3 , As2Se3 and Ge10As40S2oSe3O amorphous chalcogenide semiconductor films are connected with the photostructural changes and the reversibility of it can be applied in optical memories. With illumination by an argon ion laser at 514.5 nm or annealing near the glass-transition temperature, photobleaching was observed in the GeS2, GeSe2, Ge20As2SS55 and Ge20As25Se55 amorphous chalcogenide semiconductor films and the optical absorption edges were blue-shift. Photobleaching is reversible with photodarkening. The magnitude of shift also increased with the increase of the intensity of illumination light and the illumination time and became saturated finally. Photobleaching in amorphous chalcogenide semiconductor films is connected with the photostructural changes and includes reversible and irreversible processes. It is reversible in well-annealed films and the blue-shift can be recovered by annealing the films again. The reversibility of photobleaching can be applied in the design of the new optical storage materials. Photodarkening and photobleaching of amorphous chalcogenide semiconductor films are due to the photostructural changes. The measurements of scanning electron microscope (SEM) and transmitting electron microscope (TEM) indicated that photocrystallization was occurred in amorphous chalcogenide semiconductor films according to the light illumination. The optical heterodyned detection of optical Kerr effect (OHD-OKE) is one kind of advanced method for measuring the third-order susceptibilities of optical materials. It has been developed on the basis of optical Kerr effec (OKIE) in recent years. It is the first time to measure the third-order susceptibilities of amorphous chalcogenide semiconductor films by the method of femtosecond optical heterodyned detection of optical Kerr effect (OHD-OKE). The results indicated that the third-order susceptibilities of them were high and the response time of them was fast.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15352]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	刘启明. 硫系非晶半导体薄膜的光致性能变化的研究[D]. 中国科学院上海光学精密机械研究所. 2002.

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