Different Doping Behaviors of Silicon in Zinc Blende and Wurtzite GaAs Nanowires: Implications for Crystal-Phase Device Design

Crystal-phase engineering between zinc blende (ZB) andwurtzite(WZ) structures is becoming an important method in designing uniqueoptoelectronic and electronic semiconductor devices. Doping to engineertheir electric properties is thus of critical importance, but a directexperimental comparison in doping these two crystal structures isstill missing. Nanowires (NWs) allow the coexistence of both structuresdue to their special growth mode. The differences in dopant incorporationbetween the two phases are studied here in GaAs NW shells that arecoherently grown around the NWs, hence maintaining the crystal structureof the core. The Si dopant is observed to have a higher incorporationefficiency into the WZ structure due to a 2 times lower incorporationenergy compared with that of the ZB structure. Besides, it can alsobe predicted that Si is more inclined toward Ga sites in both structures.Indeed, the As-site doping energy of the WZ structure is several ordersof magnitude higher than that of Ga sites, allowing a lower dopingcompensation effect. This work provides useful information for dopingcontrol and hence designing crystal-phase devices.

Automated summary

Crystal-phase engineering between ZB and WZ structures is important in designing unique optoelectronic and electronic semiconductor devices. This study compares the doping differences between these two crystal structures using GaAs NW shells. Si is found to have higher incorporation efficiency into the WZ structure due to a lower incorporation energy. This work provides useful information for doping control and device design.