(Cd,Mn)Te and (Cd,Mg)Te bulk crystals are among the materials which have recently attracted attention in the field of room-temperature nuclear detector applications, where uniform semi-insulating (>109Ωcm) crystals with superior quality and homogenous distribution of internal electric field are required. We discuss crystals obtained using the low-pressure Bridgman method. The electric field distribution within the doped as-grown (Cd,Mn)Te and (Cd,Mg)Te crystals and its relationship with the resistivity are studied using the Pockels effect and a technique which uses the time-dependent charge principle. The (Cd,Mn)Te crystals are more uniform in terms of crystal quality than the (Cd,Mg)Te ones. A (Cd,Mn)Te sample which has non-uniform resistivity distribution was studied to elucidate the dependence between sample resistivity and the electric field within it. The cathode effects have been highlighted. A higher electric field observed next to the cathode is attributed to the presence of a rectifying metal–semiconductor interface. In (Cd,Mg)Te crystal a non-uniform field distribution is observed, primarily due to a strong inclination of the crystal towards twin formation. Thus, the (Cd,Mn)Te crystals seem to be more promising for nuclear detector applications than the (Cd,Mg)Te ones.