Here’s an extract from an old essay of mine, from way the heck back in 1995, submitted in PH237 at UQ, document link follows:
Bohr’s well documented opposition to Einstein’s corpuscular theory of light abated in lieu of the Bothe- Geiger experiments, in which the particle nature of radiative phenomena manifested itself. These results were in blatant contradiction with the Bohr-Kramer-Slater interpretation of the interaction between atomic systems. The B-K-S paper assumed that the radiative aspects of atomic transitions were solely describable in terms of the “wave picture”. It was this descriptive contrast which prompted Bohr to find a harmonious relationship between the particle-wave nature of the radiative aspects of quantum interactions.