Published in J. Appl. Phys. 103, 073704 (2008).
Band Offsets of InGaP/GaAs Heterojunctions by Scanning Tunneling Spectroscopy
Y. Dong (a), R. M. Feenstra (a), M. P. Semtsiv (b), and W. T. Masselink (b)
(a) Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
(b) Department of Physics, Humboldt-Universitaet zu Berlin, D-10115 Berlin, Germany
Scanning tunneling microscopy and spectroscopy are used to study InGaP/GaAs heterojunctions with InGaAs-like interfaces. Band offsets are probed using conductance spectra, with tip-induced band bending accounted for using 3-dimensional electrostatic potential simulations together with a planar computation of the tunnel current. Curve fitting of theory to experiment is performed. Using an InGaP band gap of 1.90 eV, appropriate to the disordered InGaP alloy, a valence band offset of 0.38 +/- 0.01 eV is deduced along with the corresponding conduction band offset of 0.10 +/- 0.01 eV (type I band alignment).
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