Frequency-resolved admittance measurements on InAlAs/InGaAs/InAlAs single-quantum wells to determine the conduction band offset and the capture coefficient

• Published in: Journal of the Electrochemical Society 1993-05, Vol.140 (5), p.1492-1495
• Main Authors: LOPEZ-VILLEGAS, J. M, ROURA, P, BOSCH, J, MORANTE, J. R, GEORGAKILAS, A, ZEKENTES, K
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Surface and interface electron states
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1.2221585

Frequency-resolved admittance measurements have been used to determine the conduction band offset and the capture time constant of In sub(0.52)Al sub(0.48)As/In sub(x)Ga sub(1-x)As/In sub(0.52)Al sub(0.48)As single-quantum well (SQW) structures. A theoretical analysis of the SQW admittance taking into account nonparabolicity of the conduction band is reported. Analytical expressions for both capacitance and conductance as a function of both bias and frequency have been deduced and used to fit the experimental data. As a result the conduction band offset and the capture time constant have been obtained. Two different well compositions, x = 0.53 lattice-matched and x = 0.60 strained, have been studied. In both cases the well width was 5 nm. The obtained conduction band offset at room temperature is Delta E sub(c) = 0.47 plus or minus 0.03 eV for x = 0.53 and Delta E sub(c) = 0.52 plus or minus 0.04 eV for x = 0.6. The capture coefficient of the carriers in the first subband in the well is in the range 3x10 super(-7) to 7x10 super(-7) cm super(3)/s for x = 0.53 and in the range 3x10 super(-7) to 13x10 super(-7) cm super(3)/s for x = 0.6.