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在77-300K温度下研究了Zn1-xCdxSe-ZnSe多量子阱(MQWs)的光致发光特性.首次在77K,Ar离子激光器的457.9nm激发下,在Zn0.68Cd0.32Se-ZnseMQWs中观测到5个发光带,其中三个发光带被归因于不同的激子发射:即n=1重空穴(HH)激子;n=l轻-重空穴(LH)激子和n=IHH激子同时发射两个纵光学声子的复合发光,并且n=1HH激子发光可延续至室温. 相似文献
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用经多次提纯ZnSe原料生长的ZnSe单晶在77K和高密度光激发下观测到了激子-激子(Ex-Ex)散射的P带,随激发密度增加,P带强度增加较快。而在通常的原生ZnSe单晶中只能观测到一个与激子-载流子(Ex-e)散射的Es''带,观测不到P带。经熔融锌中热处理的ZnSe单晶,在上述激发条件下,也观测到了P带。而且此带强度随热处理时间增加而增强。实验表明,P带的产生不仅与激发密度和温度有关,而且还与单晶质量有关。 相似文献
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Compositional and Structural Properties of TiO2-xNx Thin Films Deposited by Radio-Frequency Magnetron Sputtering 下载免费PDF全文
TiO2-xNx thin films are deposited onto Si(100) and quartz substrates by arf magnetron sputtering method using a titanium metal disc as a target in Ar, N2, and 02 atmospheres. The substrate temperature is kept at 300℃. The O2 and Ar gas flow rates are kept to be constants and the N gas flow rate is varied. TiO2-xNx films with different N contents are characterized by x-ray diffraction and x-ray photoelectron spectroscopy. The results indicate that the TiO2-xNx thin films can be obtained at 13% N and 15% N contents in the film, and the films with mixed TiO2 and TiN crystal can be obtained at 13% N and 15% N contents in the film. In terms of the results of x-ray photoelectron spectroscopy, N ls of β-N (396 eV) is the main component in the TiO2-xNx thin films. Because the energy level of β-N is positioned above the valence-band maximum of TiO2, an effective optical-energy gap decreases from 2.8 eV (for pure TiO2 film deposited by the same rf sputtering system) to 2.3 eV, which is verified by the optical-absorption spectra. 相似文献
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ZnTe films have been prepared on Si substrates by metal-organic chemical vapour deposition (MOCVD), and the temperature-dependent photoluminescence (PL) properties were investigated. The near-band-edge (NBE) emission of the ZnTe sample at 83K shows an asymmetry line shape, which can be decomposed into two Gaus-siam lines labelled by FE and BE. Temperature-dependent PL intensity of the NBE peak shows two variation regions, and an expression with two dissociation channels fits well to the experimental data. The results of the temperature-dependent full width at half maximum (FWHM) and peak energy were well understood under the framework of the two-dissociation-channel model. That is, at low temperature, the emission from bound excitons governs the NBE peak, while above 157K, the free exciton emission becomes dominant gradually. A simple model with three energy levels was employed to describe the variation in emission intensity of BE and FE with temperature. 相似文献
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用光助低压MOCVD进行ZnSe及ZnSe:N外延层生长,由发光光谱表明,在光助下生长的本征ZnSe外延膜具有高质量:ZnSe:N外延层中与N有关的深中心发射得到有效抑止,其p-ZnSe受主载流子深度达3×10^17cm^-3。在制备n-ZnSe/ZnCdSe-ZnSeQW/p-ZnSe结构中,在室温下观测到该二极管电脉冲下的蓝色电致发光(EL)。 相似文献
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