Semiconductor Photonic Devices

This chapter introduces the basic characteristics of light and the principles of luminescence, the difference between spontaneous emission and stimulated emission, and related devices. Semiconductor photonic devices are divided into three categories. The first type is electro‐to‐light; such devices include light‐emitting diode (LED), diode, and transistor lasers. The second type is detection of optical signals; such devices have photodetectors. The third type is optical‐to‐electricity; such devices include photovoltaic devices and solar cells. LEDs are basic devices used to replace incandescent lamps, to make display panels and LED TVs. The chapter discusses the diode laser (or laser diode). An important feature of commonly used compound semiconductors is that most of their energy bands are direct bandgap structures. For this reason, this kind of semiconductor is widely used in the manufacture of the first type of photonic devices light emitting devices, such as LEDs and lasers.