Enhancing the dot density in quantum dot infrared photodetectors via the incorporation of antimony

The authors combine optical spectroscopic studies and infrared photodetector development to demonstrate the potential of antimony-mediated InAs quantum dot growth for the production of high performance dot-based devices. By depositing 1 ML of gallium antimonide prior to dot growth, the dot density is increased from ∼3×1010 for conventional InAs dots, to ∼6×1010cm−2. Detailed intra- and interband spectroscopic studies show no significant differences in the electron energy level configuration compared with standard InAs∕GaAs dots, while intraband absorption strength is increased. Furthermore, they have implemented this growth technique to produce a quantum dot infrared photodetector with a detectivity of ∼5×1010cmHz1∕2W−1 at 7.5μm (T=77K).