Defect-initiated emission of Ga atoms from the GaAs (110) surface induced by pulsed laser irradiation
Defect-initiated emission of Ga atoms from the GaAs (110) surface induced by pulsed laser irradiation
复制标题
脉冲激光照射诱导 Ga 原子从 GaAs (110) 表面缺陷引发的发射
DOI：
10.1088/0953-8984/5/36/004
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
N. Itoh
中科院分区：
文献类型：
--
作者：
J. Kanasaki;A. Okano;K. Ishikawa;Y. Nakai;N. Itoh
作者在带隙能量1.435 eV （1.33 eV至2.53 eV）附近测量了几种光子能量的激光脉冲在GaAs（110）表面的Ga0发射产额。与Si（100）和Ga原子从GaP表面发射的情况类似，他们发现，在小于烧蚀表面影响的激光脉冲反复照射下，Ga0的发射产率从初始值开始先快速下降，然后缓慢下降，而在烧蚀阈值影响以上的激光脉冲反复照射则逐渐增加发射产率。研究发现，低于烧蚀阈值的激光脉冲的Ga0发射产额与光子能量h密切相关：h nu为1.42 eV （III区）时，Ga0发射产额相对较小。结果表明，I区的发射主要是由表面缺陷的电子激发引起的，而III区的发射主要是由涉及表面态的电子跃迁引起的。还发现，产率是激光能量的幂函数，随光子能量的变化，快速衰减分量的幂指数为2-4，缓慢衰减分量的幂指数为4-7。
The authors have measured the Ga0 emission yield from GaAs(110) surfaces for laser pulses of several photon energies near the band-gap energy 1.435 eV, ranging from 1.33 eV to 2.53 eV. Similarly to the case for emissions of Si atoms from Si(100) and of Ga atoms from GaP surfaces, they find that the Ga0 emission yield, under repeated irradiation with laser pulses at fluences smaller than that for ablating the surface, decreases from its initial value rapidly at first and then slowly, while repeated irradiation by laser pulses above the ablation threshold fluence increases the emission yield gradually. It is found that the Ga0 emission yield for laser pulses below the ablation threshold depends strongly on the photon energy h nu : the emission yield is relatively small for h nu 1.42 eV (region III). It is suggested that the emission for region I is induced by electronic excitation of defects on the surface, while that for region III is induced most dominantly by electronic transitions involving surface states. It is also found that the yield is a power function of the laser fluence with power indices 2-4 for the rapidly decaying component and 4-7 for the slowly decaying component, depending on the photon energy.