High-performance infrared photodetector based on InAs/GaAs submonolayer quantum dots grown at high temperature with a (2×4) surface reconstruction

Alzeidan, A. Cantalice, T.F., Sautter, K.E., Vallejo, K.D., Simmonds, P.J. and Quivy, A.A.

Sens. Actuators A Phys., 374, 115464 (2024).

DOI : 10.1016/j.sna.2024.115464

Abstract.

We studied the impact of surface reconstruction on the performance of infrared photodetectors containing InAs/GaAs submonolayer quantum dots (SMLQDs) grown by molecular beam epitaxy. Adjusting the substrate temperature before InAs deposition allowed us to move between the conventional c(4×4) reconstruction of the GaAs (001) surface, observed at low growth temperatures, and the (2×4) reconstruction which can only be stabilized at higher sample temperatures than those commonly used to deposit InAs. Photodetectors based on SMLQDs grown on such a (2×4) surface reconstruction outperformed those grown on a c(4×4) reconstruction and provided specific detectivities as high as 8.3×10¹¹ cm Hz^1/2 W⁻¹ at 12K. This increase in performance is due to the nucleation of true two-dimensional InAs islands which are the building blocks of SMLQDs and can only form on a (2×4)-reconstructed GaAs(001) surface.