Photoemission experiments on high-Tc superconductors: Recent progress and some open questions

We summarize some of the main results on photoemission spectroscopy in the field of high-T c superconductivity, beginning with a discussion of several open questions. We then briefly analyze our experiments that illustrate the role of doping and of intentionally introduced disorder (by electron bombardment) in Bi2Sr2CaCu2O8+x single crystals.