氧化锌薄膜的紫外光致发光的低能带尾发射

LOW ENERGY TAIL EMISSION OF ULTRAVIOLET PHOTOLUMINESCENCE FROM ZnO THIN FILMS DEPOSITED ON Si SUBSTRATES

利用直流射频磁控溅射制备了氧化锌薄膜 ,测量了不同温度下的氧化锌薄膜的光致发光 .氧化锌薄膜的室温紫外发射谱是由两个发射峰构成 ,峰的中心位置分别是在 3.31和 3.2 2eV ,它们分别为自由激子发射和自由激子的一阶声子伴线( 1 -LO) .而在 82K下 ,紫外发射谱是由光子能量分别在 3.371eV ,3.35 8eV ,3.31 6eV ,3.2 35eV和 3.1 66eV峰组成 .它们分别是自由激子 ,束缚激子和自由激子的一阶 ( 1 -LO)、二阶 ( 2 -LO)和三阶 ( 3-LO)的声子伴线 .根据变温光谱结果 ,我们提出室温下的紫外发射的低能带尾是来自自由激子的一阶声子 ( 1 -LO)

In this paper, photoluminescence of ZnO thin films, which were deposited by reactive r. f. magnetron sputtering, was investigated at various temperatures. Room-temperature ultraviolet emission spectrum of ZnO thin films consists of two peaks at 3.31 eV and 3.22 eV, which are likely assigned to the free exciton emission and optical phonon (1-LO) replica of the free exciton, respectively, while the ultraviolet emission spectrum at 82 K consists of five peaks at 3.371 eV, 3.358 eV, 3.316 eV, 3.235 eV and 3.166 eV, which are assigned to the free exciton, respectively. We think that the low energy tail emission results from the 1-LO phonon replica of the free exciton in terms of the photoluminescence spectra measured at various temperatures.