Temperature-dependent current transport measurements of p-n heterojunction diodes are very sensitive to the exact composition and doping profiles of the diode. The barrier height of the diode, determined from these measurements, in conjunction with a realistic model for the heterostructure, can be used to determine the position of the dopant junction with respect to the metallurgical junction. This type of analysis can be more sensitive than traditional characterization methods such as secondary ion mass spectroscopy or capacitance voltage profiling. The sensitivity of this technique is demonstrated using p+/n GaAs/Al0.30Ga0.70As heterojunctions grown with different zinc profiles. © 1988.