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利用气相输运方法,在(111)面硅衬底上制备了名义上原子数分数为2%的Li掺杂的ZnO纳米棒(样品A)。作为比较,我们在相同的生长条件下制备了没有任何掺杂的ZnO纳米棒(样品B)。XRD分析测试表明:样品A和样品B中的ZnO纳米棒具有纤锌矿六边形结构,没有其他氧化物,例如Li2O。Hall效应测量表明:样品A导电类型为p型,空穴载流子浓度为6.72×1016cm-3,空穴载流子迁移率为2.46 cm2.V-1.s-1。样品B为n型,电子载流子浓度为7.16×1018cm-3,电子载流子迁移率为4.73 cm2.V-1.s-1。低温光致发光光谱测试表明,样品A和样品B发光峰明显的区别是位于3.351 eV(样品B)和3.364 eV(样品A)处。根据文献报道,在没有掺杂的ZnO中,3.364 eV发光峰源于施主束缚激子发光。通过变温光致发光光谱的测试,证明了在样品A中,位于3.351 eV的发光峰源于受主束缚激子发光,其光学受主能级位于价带顶142meV处。
Li-doped ZnO nanorods with a nominal atomic fraction of 2% were prepared on the (111) surface silicon substrate by gas-phase transport (Sample A). As a comparison, we prepared ZnO nanorods without any doping under the same growth conditions (Sample B). XRD analysis tests showed that the ZnO nanorods in Sample A and Sample B have a wurtzite hexagonal structure with no other oxides such as Li2O. The Hall effect measurement shows that the conductivity type of the sample A is p type, the hole carrier concentration is 6.72 × 10 16 cm -3, and the hole carrier mobility is 2.46 cm 2 .V-1 .s-1. Sample B was n-type with an electron carrier concentration of 7.16 × 10 18 cm -3 and an electron carrier mobility of 4.73 cm 2 .V-1 .s-1. Low-temperature photoluminescence spectroscopy showed significant differences between the luminescence peaks of sample A and sample B at 3.351 eV (sample B) and 3.364 eV (sample A). According to the literature, 3.364 eV luminescence peak originates from donor-bound excitons in undoped ZnO. The results show that in the sample A, the luminescence peak at 3.351 eV originates from the acceptor-bound exciton and its optical acceptor level is at 142meV at the top of the valence band.