Al 0.3 Ga 0.7 As capping layer on the InAs quantum dots, a transverse-electric-͑TE͒ field-enhanced multicolor quantum-dot ͑QD͒ infrared photodetector has been achieved. The TE-enhanced peaks are due to the transition from the S-like ground state to the P-like first excited states induced by the strain field effects on the quantum dot. After rapid thermal annealing, the TE dominant peaks can be changed to transverse-magnetic-͑TM͒ field-enhanced and vice versa. This is because the rapid thermal

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... nealing creates defects at the boundary of QDs and their surrounding material, which release the compressive strain within the QDs.