InAs/GaAs quantum dot infrared photodetectors on on-axis Si (100) substrates

Quantum dot infrared photodetectors (QDIPs) are receiving attention as next generation infrared photodetectors that offer high-sensitivity and high-temperature operation. The realisation of QDIPs on silicon (Si) substrates offer further great advantages in terms of cost reduction and higher-resolution focal plane arrays. Indium arsenide/gallium arsenide QDIPs grown directly on on-axis Si (100) substrates are demonstrated. These are expected to further reduce fabrication costs by utilising both the monolithic integration of QDIPs with Si readout integrated circuits and also the bare substrate cost (compared with offcut Si substrates). In the device, the peak detectivity at a temperature of 32 K is measured to be 5.8 × 107 cm Hz1/2/W of 6.2 μm at a bias 0.6 V, with a corresponding responsivity of 27 mA/W. This result indicates that QD structures directly grown on on-axis Si substrates are very promising for the realisation of high-performance QDIPs with low fabrication cost.