Quantum dot infrared photodetectors (QDIPs) offer normal-incidence detection, low dark current, high operating temperature, and multi-wavelength detection. In an effort to get better responsivity in QDIPs at higher operating temperatures, we have grown, fabricated, and characterized two different QDIP heterostructures. The first is a device with 70 quantum dot layers. As a result, the peak responsivity is measured to be 0.12 A/W for V-bias = 2.0V and T = 175K. The second device has ten layers of InAs quantum dots embedded in an AlAs/GaAs superlattice. As a result of the subsequent large dot density and increased carrier confinement, the peak responsivity is measured to be 2.5 A/W for V-bias = -1.5 V and T = 78 K. (C) 2004 American Vacuum Society.