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 similar to 3x10(10) for conventional InAs dots, to similar to 6x10(10) cm(-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 similar to 5x10(10) cm Hz(1/2) W-1 at 7.5 mu m (T=77 K). (C) 2007 American Institute of Physics.