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Study of Time-Resolved Optically Detected Magnetic Resonance in Semiconductors

半导体中时间分辨光学检测磁共振的研究

基本信息

批准号：
60540196
负责人：
MORIGAKI Kazuo
金额：
$ 1.02万
依托单位：
The Institute for Solid State Physics, The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60540196/
关键词：
Optically detected magnetic resonance Amorphous silicon Superlattices Recombination processes A centres

项目摘要

We have set up the apparatus for time-resolved optically detected magnetic resonance (TRODMR) measurements operating at 9.6 GHz and 2 K. A dye laser pumped by either a pulsed <N_2> laser of 5 ns or a pulsed excimer laser of 10 ns was used as a pulsed excitation source. Using such equipment, we have carried out TRODMR experiments on a-Si:H, a- <Si_(1-x)N_x> :H and a-Si:H/a- <Si_(1-x)N_x> :H superlattices. The following results and conclusions have been obtained:1. The ODMR signal due to tail electrons in a-Si:H was observed for the first time. Thus, radiative recombination of tail electrons with trapped holes at the A centres and/or the valence band tail was clarified as a function of delay time of the microwave pulse and the gate pulse for the measurement, <t_d> , after a pulsed excitation.2. For a-Si:H/a- <Si_(1-x)N_x> :H superlattices, the confinement effect of electrons and holes in the well layer (a-Si:H) was inferred from the results of relative change in the luminescence intensity at the A centre resonance as a function of <t_d> . For superlattices not containing a number of defects at the interfaces, nonradiative recombination through dangling bonds in thin well layers was found to be suppressed compared to that for a-Si:H bulk films.3. Triplet exciton recombination was investigated by observing the g <Similar or Equal> 4 ODMR signal and the broad g <Similar or Equal> 2 ODMR signal in a-Si:H, a- <Si_(1-x)C_x> :H and a- <Si_(1-x)N_x> :H. From TRODMR experiments, it was concluded that triptet excitons decay with a time constant of <about> 1 ms in a-Si:H. From these investigations, we conclude that TRODMR technique provides a powerful means for elucidating recombination processes and nature of recombination centres in semiconductors.

我们建立了在 9.6 GHz 和 2 K 下运行的时间分辨光学检测磁共振 (TRODMR) 测量装置。使用由 5 ns 脉冲 <N_2> 激光器或 10 ns 脉冲准分子激光器泵浦的染料激光器作为脉冲激发源。利用此类设备，我们对a-Si:H、a- <Si_(1-x)N_x> :H和a-Si:H/a- <Si_(1-x)N_x> :H超晶格进行了TRODMR实验。得到以下结果和结论： 1．首次观察到a-Si:H中尾电子产生的ODMR信号。因此，在脉冲激发后，尾部电子与A中心和/或价带尾部处的捕获空穴的辐射复合被阐明为微波脉冲和用于测量的门脉冲的延迟时间的函数<t_d>。2．对于a-Si:H/a- <Si_(1-x)N_x> :H超晶格，阱层(a-Si:H)中电子和空穴的限制效应是根据A中心共振处的发光强度相对变化的结果推断为<t_d>的函数。对于界面处不包含大量缺陷的超晶格，与a-Si:H体膜相比，通过薄阱层中的悬空键进行的非辐射复合被发现受到抑制。3．通过观察 a-Si:H、a- <Si_(1-x)C_x> :H 和 a- <Si_(1-x)N_x> :H 中的 g <Similar or Equal> 4 ODMR 信号和宽 g <Similar or Equal> 2 ODMR 信号来研究三线态激子重组。根据 TRODMR 实验，得出结论：a-Si:H 中三重态激子以 <约> 1 ms 的时间常数衰减。从这些研究中，我们得出结论，TRODMR 技术为阐明半导体中的复合过程和复合中心的性质提供了一种强大的手段。