Investigation of Localized Electric Field in the Type-II InAs/GaAsSb/GaAs Structure
S.H. Lee a, J.S. Kima, S. Yoon a, Y. Kim b, S.J. Lee b and C.B. Honsberg c
aDepartment of Physics, Yeungnam University, Gyeongsan 712-749, Korea
bDivision of Convergence Technology, Korea Research Institute of Standards and Science, Daejeon 305-340, Korea
cSchool of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA
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The effect of localized electric field (F) was investigated in the type-II InAs/GaAsSb/GaAs structures. To compare type-I to type-II, two types of samples with different Sb contents was grown by molecular beam epitaxy, whose Sb contents are 3% (type-I) and 16% (type-II), respectively. In the both samples, we performed excitation power dependent-photoreflectance at 10 K and the result showed that the period of the Franz-Keldysh oscillation, revealed above the band gap (Eg) of GaAs, was broadened in the only type-II system, which means that F was also increased because it is proportional to the period of the Franz-Keldysh oscillation while the period of the Franz-Keldysh oscillations stayed unchanged in type-I system. This phenomenon is explained by that the F was affected by the band bending effect caused by the spatially separated photo-excited carriers in the interface between GaAsSb and GaAs. The F changed linearly as a function of square root of excitation power as expected for the F. Moreover, F was calculated using fast Fourier transform: method for a qualitative analysis, which is in a good agreement with the theory of triangular well approximation.

DOI: 10.12693/APhysPolA.130.1213
PACS numbers: 78.66.Fd, 78.40.-q, 73.40.Lq, 73.50.Pz