飞秒激光对p型HgCdTe打孔形成PN结.该实验基于1 kHz低重复频率飞秒激光采用不同脉冲数在p型HgCdTe上打孔形成尺寸不同的微孔结构.实验发现脉冲数是影响成结效果的重要参数.激光诱导电流(LBIC)检测表明,随着脉冲数由单个增至10个,微孔侧壁反型层宽度由13.5 μm减小到10.5 μm.当脉冲数增大至100个时,微孔LBIC信号曲线已严重偏离PN结所对应的正负峰对称线形,意味着结特性趋于失效.对LBIC曲线拟合表明,单脉冲打孔形成的PN结给出最大的载流子扩散长度,约为17 μm,而10个脉冲对应的环孔PN结扩散长度则减小为12 μm.

Femtosecond laser drilling induces PN junction in p-HgCdTe. In this work, femtosecond laser with repetition rate of 1 kHz was used to generate different micrometer-sized holes. It was found that the pulse number is an important parameter which influences the effect of junction formation. Laser beam induced current (LBIC) characterization shows that the inversion layer thickness reduces from 13.5 μm to 10.5 μm when the pulses increase from one to ten. The LBIC profile of a hole created with one hundred pulses deviates severely from the line shape of ideal PN junction, resulting in large leakage current. In addition, the fitting of LBIC curves shows that the diffusion length of the hole created by a single pulse is 17 μm whereas the one created by ten pulses reduces to 12 μm.