激光暗荧光光谱电场测量微扰计算与实验

为了实现强流脉冲电子束对材料表面改性的工业化应用,需要对电子束的作用过程进行实时微扰监测。电场强度是反映电子束特性的关键参数之一,基于Stark效应的激光暗荧光光谱可实现对环境电场的微扰测量。因此,开展激光功率密度对环境电场的影响研究,对此类电场测量方法的参数设置和结果判断具有重要的理论和应用价值。通过理论分析和计算得出电场测量微扰状态下的激光功率密度与试验环境的关系模型。基于上述关系模型,搭建测试平台,验证激光功率密度对电场测量微扰的情况。实验结果表明:在示踪气体氙气压强为1.0×10^(-4)mbar、电场强度不大于2 kV/cm的条件下,对电场测量微扰的激光功率密度值为5 MW/cm^(2),与理论计算值基本一致。研究结果填补了激光暗荧光光谱诊断方法中激光功率密度对电场影响定量分析的空白,可应用于同类电场测量方法中,为激光功率密度与实验参数的设置提供依据和参照,有效支撑电场测量实验的开展,有效提升电场测量的准确性。

Modulating the threshold voltage of oxide nanowire field-effect transistors by a Ga^＋ ion beam

In this paper, we report a method to change the threshold voltage of SnO2 and In2O3 nanowire transistors by Ga^＋ ion irradiation. Unlike the results in earlier reports, the threshold voltages of SnO2 and In2O3 nanowire field-effect transistors （FETs） shift in the negative gate voltage direction after Ga^＋ ion irradiation. Smaller threshold voltages, achieved by Ga^＋ ion irradiation, are required for high-performance and low-voltage operation. The threshold voltage shift can be attributed to the degradation of surface defects caused by Ga＋ ion irradiation. After irradiation, the current on/off ratio declines slightly, but is still close to -106. The results indicate that Ga^＋ ion beam irradiation plays a vital role in improving the performance of oxide nanowire FETs.