Experimental study of ultrafast carrier dynamics in polycrystalline ZnTe nanofilm
文献类型：期刊论文
| 作者 | Jia Lin1; Tang Da-Wei2; Zhang Xing1 |
| 刊名 | ACTA PHYSICA SINICA
 |
| 出版日期 | 2015-04-20 |
| 卷号 | 64期号:8 |
| 关键词 | zinc telluride polycrystalline femtosecond laser carrier |
| 英文摘要 | Zinc telluride, due to its direct band gap and broadband light absorption, has the good application prospects in terahertz devices, solar cells, waveguide devices, and green light emitting diodes. In the photovoltaic field, it is possible to further improve the photoelectron conversion efficiency of multi-junction tandem solar cells by combining zinc telluride with III-V semiconductors. Ultrafast photo-excited carrier dynamics is fundamental to understand photoelectron conversion process of nanofilm solar cells. In this study, the ultrafast energy carrier dynamics of N-doped polycrystalline zinc telluride is investigated by using the femtosecond laser two-color pump-probe method at room temperature. The polycrystalline zinc telluride nanofilm is grown on a 500 mu m GaAs (001) substrate via molecular beam epitaxy and doped by using a nitrogen ratio frequency plasma cell. The laser pulses with a central wavelength of 800 nm are divided into pump beam and probe beam by a beam splitter, after which the pump beam passes through a bismuth triborate crystal and its frequency is doubled to 400 nm. The 400 nm pump beam and 800 nm probe beam are focused on the sample collinearly through the same objective lens. Photo-excited carriers will be generated since the excitation photon energy of 400 nm pump beam (3.1 eV) is higher than the band gap of zinc telluride (similar to 2.39 eV). The experimental data are analyzed by using the theoretical fitting model which includes energy relaxation processes of electrons and lattice, and the theoretical curves are consistent well with the experimental data. The fitted results show that the three dominated relaxation processes which affect the initial reflectivity recovery are in sub-picosecond time regime. The positive amplitude electron relaxation process is attributed to inter-band carrier cooling and carrier diffusion through electron-photon interactions, and the deduced decay time of this positive amplitude electron relaxation process is about 0.75 ps. The negative amplitude electron relaxation process is characterized as a photo-generated carrier trapping process induced by defects, and the decay time of this process is about 0.61 ps. The lattice heating process is realized through electron-phonon coupling process, and the calculated time constant of the lattice heating is about 0.86 ps. |
| WOS标题词 | Science & Technology ; Physical Sciences |
| 类目[WOS] | Physics, Multidisciplinary |
| 研究领域[WOS] | Physics |
| 关键词[WOS] | EPITAXY |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000354059200043 |
| 公开日期 | 2015-12-22 |
| 源URL | [http://ir.etp.ac.cn/handle/311046/98921]  |
| 专题 | 工程热物理研究所_中国科学院工程热物理所（论文库）_期刊论文（SCI） |
| 作者单位 | 1.Tsinghua Univ, Sch Aerosp, Minist Educ, Key Lab Thermal Sci & Power Engn, Beijing 100084, Peoples R China 2.Chinese Acad Sci, Inst Engn Thermophys, Beijing 100190, Peoples R China |
| 推荐引用方式 GB/T 7714 | Jia Lin,Tang Da-Wei,Zhang Xing. Experimental study of ultrafast carrier dynamics in polycrystalline ZnTe nanofilm[J]. ACTA PHYSICA SINICA,2015,64(8). |
| APA | Jia Lin,Tang Da-Wei,&Zhang Xing.(2015).Experimental study of ultrafast carrier dynamics in polycrystalline ZnTe nanofilm.ACTA PHYSICA SINICA,64(8). |
| MLA | Jia Lin,et al."Experimental study of ultrafast carrier dynamics in polycrystalline ZnTe nanofilm".ACTA PHYSICA SINICA 64.8(2015). |
入库方式： OAI收割
来源：工程热物理研究所
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