Modulation Spectroscopy of GaAs Covered by InAs Quantum Dots
JIN Peng1, MENG Xian-Quan1, ZHANG Zi-Yang1, LI Cheng-Ming1, QU Sheng-Chun1, XU Bo1, LIU Feng-Qi1, WANG Zhan-Guo1, LI Yi-Gang2, ZHANG Cun-Zhou2, PAN Shi-Hong2
1Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing 100083
2Department of Physics, Nankai University, Tianjin 300071
Modulation Spectroscopy of GaAs Covered by InAs Quantum Dots
1Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing 100083
2Department of Physics, Nankai University, Tianjin 300071
Abstract： Contactless electroreflectance has been employed at room temperature to study the Fermi level pinning at undoped-n+ GaAs surface covered by 1.6 and 1.8 monolayer (ML) InAs quantum dots (QDs). It is shown that the 1.8 ML InAs QDs moves the Fermi level at GaAs surface to the valence band maximum by about 70 meV compared to bare GaAs, whereas 1.6 ML InAs on GaAs does not modify the Fermi level. It is confirmed that the modification of the 1.8 ML InAs deposition on the Fermi level at GaAs surface is due to the QDs, which are surrounded by some oxidized InAs facets, rather than the wetting layer.
2002, Vol. 19 
