Photoexcitation-induced current sensing on semi-insulating GaAs using a tunneling microscope tip

Kenji Kawashima; Shinji Takai; Gou Kudou; Hideo Adachi; Misaichi Takeuchi; Kenzo Fujiwara

doi:10.1117/12.369365

11 November 1999 Photoexcitation-induced current sensing on semi-insulating GaAs using a tunneling microscope tip

Kenji Kawashima, Shinji Takai, Gou Kudou, Hideo Adachi, Misaichi Takeuchi, Kenzo Fujiwara

Proceedings Volume 3897, Advanced Photonic Sensors and Applications; (1999) https://doi.org/10.1117/12.369365
Event: International Symposium on Photonics and Applications, 1999, Singapore, Singapore

Abstract

Detailed tunneling current measurements using a tunneling microscope tip have been performed on semi-insulating GaAs surfaces as a function of illumination power, Pt/Ir tip- surface distance, and separation between the tip and In/Ga electrode on the sample surface to elucidate previously unsolved problems of illumination-induced thermal expansion effects on the probe and of the surface depletion effects. We show that the tip-sample distance to detect a constant tunneling current is extended with increasing the otpical excitation power. It is also found that the photo-induced tunneling current as high as 8 nA driven by a 746 nm laser diode is linearly proportional to the optical excitation power. This photo-induced carriers conduction is also confirmed by studying the transient photocurrent responses, which is slowed down by increasing the tip-to-electrode distance. These results reveal that, in our case, the thermal effects are negligible and photogenerated electron tunneling is a dominant mechanism for the increased tunneling current from the samples surface biased at negative voltages relative to the tip.

Citation Download Citation

Kenji Kawashima, Shinji Takai, Gou Kudou, Hideo Adachi, Misaichi Takeuchi, and Kenzo Fujiwara "Photoexcitation-induced current sensing on semi-insulating GaAs using a tunneling microscope tip", Proc. SPIE 3897, Advanced Photonic Sensors and Applications, (11 November 1999); https://doi.org/10.1117/12.369365

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