In this paper, we describe the energy levels of GaAs/AlGaAs quantum well st
ructure used in quantum well Infrared photodetector (QWIP). The photorespon
se and photoluminescent spectrum of quantum well material were measured. Th
e experiment and simulation show that the width of the well and the Al mola
r ratio of QWIP should be 4.7nm and 0.29, separately, if the peak wavelengt
h of QWIP is expected to be at 8 mu m.