QQ客服 官方微博 反馈留言

浏览/检索结果: 共4条，第1-4条 帮助 已选(0)清除 条数/页：5101520253035404550556065707580859095100   排序方式：请选择作者升序作者降序题名升序题名降序发表日期升序发表日期降序提交时间升序提交时间降序 Si基Ge/SiGeⅠ型量子阱结构的理论设计和实验研究 期刊论文 2012 陈城钊; 陈阳华; 黄诗浩; 李成; 赖虹凯; 陈松岩 收藏  |  浏览/下载：4/0  |  提交时间：2016/05/17 能带工程理论  Ge/SiGe  量子阱  室温荧光(PL)光谱  energy band engineering theory  Ge/SiGe  quantum well  room temperature photoluminescence(PL) spectra   Effect of interface on luminescence properties in ZnO/MgZnO heterostructures (EI CONFERENCE) 会议论文 Wei Z. P.; Lu Y. M.; Shen D. Z.; Wu C. X.; Zhang Z. Z.; Zhao D. X.; Zhang J. Y.; Fan X. W. 收藏  |  浏览/下载：18/0  |  提交时间：2013/03/25 A set of ZnO/MgZnO heterostructures with well widths  Lw  varying from 2 to 20 nm has been grown by plasma-assisted molecular-beam epitaxy (P-MBE). We present a room-temperature (RT) study of the well-width-dependent photoluminescence (PL) spectra and carrier lifetimes in ZnO/MgZnO heterostructures. Bi-exponential process is seen at RT time-decay curves of the luminescence from the well layers. The fast process is from the recombination of the free exciton  while the slow process is attributing to the recombination of the localized exciton in the interface of ZnO and MgZnO. It is also confirmed from the PL peak shift of time-resolved PL spectra. With decreasing the well thickness  the fast process gradually increases and dominantly contributes to the PL spectrum due to the interface improvement. 2006 Elsevier B.V. All rights reserved.   Excitonic properties of vertically aligned ZnO nanotubes under high-density excitation (EI CONFERENCE) 会议论文 Lu Y. M.; Liang H. W.; Shen D. Z.; Zhang Z. Z.; Zhang J. Y.; Zhao D. X.; Liu Y. C.; Fan X. W. 收藏  |  浏览/下载：10/0  |  提交时间：2013/03/25 In this paper  highly oriented and vertically arranged ZnO nanotubes are prepared on Al2O3 (0 0 0 1) substrate without employing any metal catalysts by plasma-assisted molecular beam epitaxy. The photoluminescence (PL) spectra at room temperature are studied under high excitation densities. Under lower excitation density (60 kW/cm2)  PL spectrum shows that one strong free exciton emission (FE) locates at 3.306 eV. As the excitation density increases up to 200 kW/cm2  a new emission peak (Pn) located at low-energy side of FE is attributed to the spontaneous emission due to an exciton-exciton (Ex-E x) scattering process from two ground state excitons  where one exciton is recombined by emitting a photon and the other is scattered into the excited states of n=2  3  4.... Under excitation density of 300 kW/cm 2  the stimulated emission originating from Ex-E x scattering is obtained. When the excitation density is above 580 kW/cm2  the emission from electron-hole plasma is observed in low-energy side of the P band and indicates a typical superradiation recombination processes with increasing excitation density. 2006 Elsevier B.V. All rights reserved.   Characterization of ZnO/Mg0.12Zn0.88O heterostructure grown by plasma-assisted molecular beam epitaxy (EI CONFERENCE) 会议论文 13th International Conference on Molecular Beam Epitaxy, August 22, 2004 - August 27, 2004, 13th International Conference on Molecular Beam Epitaxy, August 22, 2004 - August 27, 2004 Lu Y. M.; Wu C. X.; Wei Z. P.; Zhang Z. Z.; Zhao D. X.; Zhang J. Y.; Liu Y. C.; Shen D. Z.; Fan X. W. 收藏  |  浏览/下载：21/0  |  提交时间：2013/03/25 In this paper  Mg0.12Zn0.88O/ZnO heterostructures were fabricated on c-plane sapphire (Al2O3) substrates by plasma-assisted molecular beam epitaxy (P-MBE). The quality of the Mg 0.12Zn0.88O alloy thin film was characterized by X-ray diffraction (XRD) and reflection high-energy electron diffraction (RHEED). Optical properties of the Mg0.12Zn0.88O/ZnO heterostructure were studied by absorption and photoluminescence (PL) spectra. At room temperature (RT)  Mg0.12Zn0.88O/ZnO heterostructures show two absorption edges originating from ZnO and Mg 0.12Zn0.88O layers  respectively. In PL spectra  two ultraviolet emission bands related to the ZnO layer and the Mg 0.12Zn0.88O layer were observed. The emission band from Mg0.12Zn0.88O layer dominates at moderately lower temperature  and the luminescence of ZnO becomes gradually important with increasing temperature. This is suggested to exist as a potential barrier in the interface and to restrict the relaxation of the carriers from the Mg 0.12Zn0.88O layer to ZnO layer. As the thickness of ZnO layer decreases  the emission from the Mg0.12Zn0.88O layer becomes weaker and weaker. When the ZnO thickness is up to 2 nm  only the luminescence of the ZnO layer is observed at RT. The quenching of the emission corresponding to the MgZnO layer indicates the existence of a strong injection process in the samples with thinner ZnO layer. 2005 Elsevier B.V. All rights reserved.