Investigation of Impurities in type-II InAs/GaSb Superlattices via Capacitance-Voltage Measurement
NORTHWESTERN UNIV EVANSTON IL OFFICE OF RESEARCH SPONSORED PROJECTS
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Capacitance-voltage measurement was utilized to characterize impurities in the non-intentionally doped region of Type-II InAsGaSb superlattice p-i-n photodiodes. Ionized carrier concentration versus temperature dependence revealed the presence of a kind of defects with activation energy below 6meV and a total concentration of low 1015 cm 3. Correlation between defect characteristics and superlattice designs was studied. The defects exhibited a p-type behavior with decreasing activation energy as the InAs thickness increased from 7 to 11 monolayers, while maintaining the GaSb thickness of 7 monolayers. With 13 monolayers of InAs, the superlattice became n-type and the activation energy deviated from the p-type trend.
- Electricity and Magnetism