Selective area epitaxy is a promising approach to definenanowirenetworks for topological quantum computing. However, it is challengingto concurrently engineer nanowire morphology, for carrier confinement,and precision doping, to tune carrier density. We report a strategyto promote Si dopant incorporation and suppress dopant diffusion inremote doped InGaAs nanowires templated by GaAs nanomembrane networks.Growth of a dilute AlGaAs layer following doping of the GaAs nanomembraneinduces incorporation of Si that otherwise segregates to the growthsurface, enabling precise control of the spacing between the Si donorsand the undoped InGaAs channel; a simple model captures the influenceof Al on the Si incorporation rate. Finite element modeling confirmsthat a high electron density is produced in the channel.