Basic study on modurated field emission using semiconductor field emitter arrays

频率范围从微波到太赫兹波的调制电子束的产生提供了一种高效、频率可调、中功率、紧凑的频率电磁波源。半导体FEA由于在半导体发射极尖端中产生电子-空穴对而通过光激发产生过量发射电流。然后，利用飞秒激光脉冲和两束连续的、频率偏移的泵浦光，产生了太赫兹频率以上的调制光束，制备了p型Si FEA，并对其发射特性进行了测试。结果表明，受p型衬底中少数载流子浓度的限制，发射电流处于饱和状态，饱和区的电流稳定度小于平均发射电流的10%。此外，由于半导体发射极尖端中电子-空穴对的产生，来自p型Si FEA的发射电流由激光强度和衬底温度控制。

The generation of moduration electron beam at the frequency renges from microwave to teraherz wave provides a highly efficient, frequency tunable, midium power and compact electro-magnetic wave sources at the frequencies. A semiconductor FEA produces excess emission current by photo-excitation due to generation of electron-hole pair in the semiconductor emitter tips. Then, a moduration beam over terahertz frequency is produced by photo-excitation of femtosecond laser pulses and two continuous and frequency-offset pump laser.We fabricated p-type Si FEA and examined the emission characteristics. It was verified that the emissioncurrent was saturated by the limitation of the minority carrier density in the p-type substrate and the current stabirity in the saturation ragion was less than 10% of average emission current. Additionally, the emission current from p-type Si FEA was controlled by the laser intensity and the temperature of the substrate due to generation of electron-hole pair in the semiconductor emitter tips.