GaAs doped by self-assembled molecular monolayers

Self-assembled molecular monolayer doping remains as a research focus for its nature of being conformal, nondestructive, and self-limiting. Herein, we demonstrate a sulfur monolayer doping in GaAs, facilitated by (NH4)2Sx solution. The Van der Pauw technique, secondary-ion mass spectroscopy, and low-temperature Hall effect measurements show that the sulfur dopants concentration and electron activation rate are 4*10^20 cm-3 and 77.6%, respectively. The donor energy level of sulfur-doped GaAs is located 68 meV below the conduction band. Based on this process, a p-n junction was successfully fabricated on highly doped p-type GaAs substrate.