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采用射频磁控溅射技术,在不同温度下制备了N掺杂Cu_2O薄膜.透射光谱分析发现,N掺杂导致Cu_2O成为允许的带隙直接跃迁半导体,并使Cu_2O的光学禁带宽度增加.不同温度下沉积的薄膜光学禁带宽度E_g=2.52±0.03 eV.第一性原理计算表明,N掺杂导致Cu_2O的禁带宽度增加了约25%,主要与价带顶下移和导带底上移有关,与实验报道基本符合.N的2p电子态分布不同于O原子,在价带顶附近具有较大的态密度是N掺杂Cu_2O变成允许的带隙直接跃迁半导体的根本原因.
N-doped Cu 2 O thin films were prepared by RF magnetron sputtering at different temperatures.It was found by transmittance spectroscopy that N-doping caused Cu 2 O to be a direct bandgap semiconductor with an increased bandgap of Cu 2 O The optical band gap E_g = 2.52 ± 0.03 eV. The first-principles calculations show that the doping width of Cu_2O is increased by about 25% due to N doping, which is mainly related to the downward movement of valence band and the bottom of conduction band The experimental results show that the 2p electron state distribution of N is different from that of O atom, and the larger density of states near the top of the valence band is the fundamental reason that N-doped Cu 2 O becomes an allowed band gap direct transition semiconductor.