Demonstration of Si based InAs/GaSb type-II superlattice p-i-n photodetector

In this paper, mid-wave infrared photodetection based on an InAs/GaSb type-II superlattice p-i-n photodetector grown directly on Si substrate is demonstrated and characterized. Excitation power dependence on integrated intensity from the photoluminescence measurements reveals a power coefficient of P ∼ I0.74, indicating that defects related process is playing an important role in the predominant recombination channel for photogenerated carriers. At 70 K, the device exhibits a dark current density of 2.3 A/cm2 under −0.1 V bias. Arrhenius analysis of dark current shows activation energies much less than half of the active layer bandgap, which suggests that the device is mainly limited by surface leakage and defect-related generation-recombination, consistent with the photoluminescence analysis. The detector shows 50% cutoff wavelength at ∼5.5 µm at 70 K under bias of −0.1 V. The corresponding peak responsivity and specific detectivity are 1.2 A/W and 1.3 × 109 cm∙Hz1/2/W, respectively. Based on these optoelectronics characterization results, reduction of defects by optimizing the III/V-Si interface and material growth quality are argued to be the main factors for performance improvement in this Si-based T2SL detector towards low cost, large-format MWIR detection system on Si photonics platform.