Hi, I have this report to do on "Charge injection in heterostructures". I have been searching and reading but I still have some trouble with the basics, i.e. defining the concept. As far as I understood a heterostructure is a junction between two or more different semiconductors and the carrier injections comes in the sense of bringing electrons and/or holes to the heterostructure through some kind of contact as a way of making a current or a light emitter by electron-hole recombination. So the first question, is this correct? What is difference between this and conduction through a metal-semiconductor contact? Is there such thing as a metal-heterostructure contact? Does electron-hole pair formation by light counts as charge injection? What is super-injection? Can you advise me with some bibliography about this topic? I'm really having trouble expanding this concept in details. Thanks for the help.