GaSb TPV devices are commonly manufactured by Zn diffusion from the vapour phase on a n‐type substrate, leading to very high doping concentrations in a narrow emitter. This fact emphasizes the need of a careful modelling that must include high doping effects to simulate the optoelectronic behaviour of devices. In this work the key parameters that have strong influence on the performance of GaSb TPV devices are underlined, more reliable values are suggested and our first results on the study of the absorption coefficient dependence with p‐type high doping concentration are presented. © 2003 American Institute of Physics