TABLE OF CONTENTS In this section we will consider the basic photon absorption and emission processes in semiconductors. To understand the optical processes we need not only to use the quantum description of electrons (i.e., band theory), but also the quantum description for light. In quantum mechanics, classical waves, such as electromagnetic waves, sound waves, etc., behave as particles, and this particle nature becomes critical under some conditions. Light waves, which are electromagnetic waves, behave as photons of energy ? ?. In simple processes electron-photon interaction changes the electron energy by + ? ? (absorption) or ? ? ? (emission), as shown in Fig. 5.5.
The full understanding of electron-photon interaction requires details of quantum mechanics, which are beyond the scope of this book. Here we will provide some physical motivation for the processes and then discuss the results.
We will now discuss how electrons in a semiconductor respond to electromagnetic fields or photons. The interaction of electrons and photons is the basis of all semiconductor optoelectronic devices. There are two kinds of events that occur when electron-photon interactions occur: (i) absorption of photons, where the electron gains energy by absorbing a photon; and (ii) emission, where the electron emits a photon...
