Trimethyl aluminium (TMA) was used as an intrinsic dopant source to grow highly p-doped AlGaAs by chemical beam epitaxy (CBE). Growth parameters were varied to control doping level, and three sets of growth parameters were identified to maximize the hole concentration in CBE-grown AlGaAs: low temperature growth; low V/III ratio combined with high growth rate; aluminium-rich composition. AlGaAs/GaAs tunnel junctions were fabricated using each of these set of growth parameters and tunneling peak currents as high as 6136 A/cm(2) were obtained. These tunnel junctions are suitable for use in very high concentration multijunction solar cells. (c) 2013 Elsevier B.V. All rights reserved.