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991.
By the method of finite difference, the anisotropic spin splitting of the AlxGa1-xAs/GaAs/Aly Ga1-yAs/AlxGal-xAs step quantum wells (QWs) are theoretically investigated considering the interplay of the bulk inversion asymmetry and structure inversion asymmetry induced by step quantum well structure and external electric field. We demonstrate that the anisotropy of the total spin splitting can be controlled by the shape of the QWs and the external electric field. The interface related Rashba effect plays an important effect on the anisotropic spin splitting by influencing the magnitude of the spin splitting and the direction of electron spin. The Rashba spin splitting presents in the step quantum wells due to the interface related Rashba effect even without external electric field or magnetic field. 相似文献
992.
Li-N dual-doped p-type ZnO (ZnO:(Li, N)) thin films are prepared by pulsed laser deposition. The optical properties are studied using temperature-dependent photoluminescence. The Lizn-No complex acceptor with an energy 1evel of 138 me V is identified from the free-to-neutral-acceptor (e, A0 ) emission. The Haynes factor is about 0.087 for the Lizn-No complex acceptor, with the acceptor bound-exciton binding energy of 12meV. Another deeper acceptor state located at 248 meV, also identified from the (e, A0) emission, is attributed to zinc vacancy acceptor. The two acceptor states might both contribute to the observed p-type conductivity in ZnO:(Li,N). 相似文献
993.
Effect of Different Substrate Temperature on Phosphorus-Doped ZnO Thin Films Prepared by PLD on Sapphire Substrates 下载免费PDF全文
Phosphorus-doped ZnO (ZnO:P) thin films are deposited on a c-plane sapphire in oxygen at 350℃, 450℃, 550℃ and 650℃, respectively, by pulsed laser deposition (PLD), then all the ZnO:P samples are annealed at 650℃ in oxygen with a pressure of 1 × 10^5 Pa. X-ray diffraction measurements indicate that the crystalline quality of the ZnO:P thin films is improved with the increasing substrate temperature from 350℃ to 550℃. With a further increase of the deposition temperature, the crystalline quality of the ZnO:P sample is degraded. The measurements of low-temperature photoluminescence spectra demonstrate that the samples deposited at the substrate temperatures of 350℃ and 450℃ show a strong acceptor-bound exciton (A^0X) emission. The electrical properties of ZnO:P films strongly depend on the deposition temperature. The ZnO:P samples deposited at 350℃ and 450℃ exhibit p-type conductivity. The p-type ZnO:P film deposited at 450℃ shows a resistivity of 1.846Ω·cm and a relatively high hole concentration of 5.100 × 10^17 cm^-3 at room temperature. 相似文献
994.
Intrinsic Bistability and Critical Slowing in Tm^3+/Yb^3+ Codoped Laser Crystal with the Photon Avalanche Mechanism 下载免费PDF全文
We present theoretically a novel intrinsic optical bistability (IOB) in the Tm^3+ /Yb^3+ codoped system with a photon avalanche mechanism. Numerical simulations based on the rate equation model demonstrate distinct 10B hysteresis and critical slowing dynamics around the avalanche thresholds. Such an 10B characteristic in Tm^3+ /Yb^3+ eodoped crystal has potential applications in solid-state bistable optical displays and luminescence switchers in visible-infrared spectra. 相似文献
995.
996.
本文介绍了在自行研制的选择性非催化还原(SNCR)烟气脱硝试验台上采用改进型TB系列喷嘴深入烟道内部逆流喷入的方式,进行了冷态混合试验和气态氨作还原剂及CH4作添加剂的热态脱硝试验.深入烟道内部的喷入方式在提高喷入气体与烟道主气流的混合效果上明显优于侧壁圆孔喷入.在NH3/NOx=1.25,反应温度为925℃时可得到82.53%的脱硝效率,有CH4作添加剂时,温度为875℃时可得到72.37%的脱硝效率.以NOx去除率高于50%为标准,温度窗口为863~937℃;有CH4作添加剂的温度窗口为803~929℃.随着氨氮比的增大NOx去除效率也增大,但在最优温度下当氨氮比大于1.0后NOx去除率的增大不再明显.随着温度的升高,达到NOx最大去除率所需的CH4添加量减小,CH4作添加剂可大大减小氨的泄漏量. 相似文献
997.
998.
999.
Mechanism of terahertz (THz) pulse generation in gases irradiated by ultrashort laser pulses is investigated theoretically. Quasi-static transverse currents produced by laser field ionization of gases and the longitudinal modulation in formed plasmas are responsible for the THz emission at the electron plasma frequency, as demonstrated by particle-in-cell simulations including field ionization. The THz field amplitude scaling with the laser amplitude within a large range is also discussed. 相似文献
1000.