Laplace deep level transient spectroscopy of electron traps in epitaxial metalorganic chemical vapor deposition grown n-GaSb

Abstract

Three prominent electron traps, 0.167 eV, 0.243 eV, and 0.295 eV below the conduction band minimum were detected in Te doped MOCVD grown n-GaSb using an Au Schottky barrier diode. The free carrier concentration of the ∼3 μm epilayer grown on n+ (>1018 cm−3) substrate, confirmed by Hall and capacitance-voltage measurements, was 5–7 × 1016 cm−3. The low doping concentration of the epitaxial layers was achieved using diethyl tellurium as the dopant source. Defect concentration profiles suggest that Ec-0.167 eV and Ec-0.243 are predominantly confined to the surface of the epilayer and that the concentration, thereof, approximates the free carrier concentration of the material close to the metal-semiconductor interface.