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Low-temperature photoluminescence (PL) and optical absorption are carried out on a Ti-doped ZnTe bulk crystal with carefully optimized experimental conditions. The influence of excitation energy in the PL is checked. Two zero-phonon lines (ZPLs) are clearly identified and phonon sidebands are evidenced in the PL and in the absorption, respectively. A relation is established between the PL and the absorption for the intensity ratio of the two ZPLs. Thereby, the Ti ion is identified as Ti 3+ and the ZPLs in the PL spectrum are from the 7 and 8 levels of the 2 T 2 excited state to the well-separated 8 level of the 2 E ground state. The separation of the two excited levels is 2.4 cm −1 . The population numbers are shown to be fully thermalized in the 2 T 2 excited state in the PL process.

Articles you may be interested inOptical determination of the electron effective mass of strain compensated In 0.4 Ga 0.6 As 0.995 N 0.005 ∕ Ga As single quantum well Modeling and analysis of photomodulated reflectance and double crystal x-ray diffraction measurements of tensilely strained InGaAs/InGaAsP quantum well structures Two types of forbidden transitions are identified in In 1Ϫx Ga x As/InP undoped quantum wells ͑QWs͒ with compressive strain by low-temperature ͑1.8 K͒ magneto-optical absorption. One of them is due to the interband transitions with different principal quantum numbers and is observable mainly in a low magnetic field and the other corresponds to P-and D-type exciton states and gets stronger as the magnetic field increases. By analyzing the forbidden transitions the in-plane effective masses of electrons (m e, * ) and heavy holes (m h, * ) are simultaneously determined, together with the z-direction ͑growth-direction͒ ones (m e,z * ,m h,z * ). The theoretically predicted relation among the electron effective masses ͓Sugawara et al., Phys. Rev. B 48, 8102 ͑1993͔͒, m e,⌫ 6 Ͻm e, * Ͻm e,z * , where m e,⌫ 6 is the band-edge electron effective mass of bulk material, is therefore verified. The difference between the values of m e,z * and m e, * is found to decrease as the strain in the QW drops. [This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to ] IP: 130.88.90.140 On: Tue, 25 Nov 2014 12:44:52where E A is the band-edge energy of the QW material, E e,n z and E h,n Ј z are the energy levels of the electrons and holes, respectively, n (nЈ) denotes the principal quantum number of the electron ͑hole͒ energy level, and E r represents the change to the exciton energy caused by the external magnetic field.As well established, E e,n z and E h,n Ј

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