Q- Would there be any current flow when we connect both ends of a diode and can we measure it using multimeter?
Ans: Well when we connect both sides of a diode, it is actually the same case when we connect the n-type and p-type material at the junction. There would be diffusion of charges i.e. holes flowing from p-side to n-side and electrons flowing from n-side to p-side. Hence there would be recombination of electrons and holes and so there be formation of depletion region at the ends too as shown below:
Hence there would be flow of charge carriers for very small time till the barrier voltage is developed. So we’ll have very small amount of current flowing that even for very small time.
But this current cannot be measured or detected using multimeter.