Two-Color Qauntum-Dot Infrared Photodetectors With Periodic Cross Metal Hole Array Contact

The two-color quantum-dot infrared photodetector (QDIP) has been fabricated successfully by the use of top metal contact perforated with cross hole arrays. One transmission peak is located at 4-6 ¿m; the other is located at 8-10 ¿m . The periodic contact metal hole arrays play double roles, i.e., the top contact and the optical filter. Patterning with lattice constants
a
= 1.6 ¿m and
a
= 2.8 ¿m, the 4- to 6-¿m and 8- to 11-¿m wavelength ranges can be detected. The two-color QDIP detectivity can be increased up to 1.85 ×10
¹¹
cmHz
^1/2
/W at 20 K and the background limited temperature is between 60 K-70 K. It can be applied to fabricate focal plane arrays.