Performance Improvement of AlGaAs/GaAs QWIP by ${\rm NH}_{3}$ Plasma Treatment

The performance of AlGaAs/GaAs quantum well infrared photodetectors (QWIPs) with and without NH₃ plasma treatment are investigated. It is demonstrated that the NH₃ plasma treatment not only gets rid of the oxide defects, such as Ga₂O₃, As₂O₃, and As₂O₅, but also prevents the formation of oxides on the GaAs surface when exposed to atmosphere for one month. The peak responsivity of the QWIPs without NH₃ plasma treatment is 0.48 A/W, and the detectivity is 3.13×10⁹ cm-Hz^1/2/W at 1.5 V and 60 K. However, the QWIP after the 10-m NH₃ plasma treatment exhibits a better performance. The highest operation temperature can be increased from 60 to 90 K. At 90 K, the peak responsivity of the QWIP is 1.25 A/W and the detectivity is 3.54×10⁹ cm-Hz^1/2/W at 1.5 V.