ABSTRACT
This chapter introduces quantum wells by discussing their basic physics, their structure, fabrication technologies, and their elementary linear optical properties. Many of the physical effects in quantum well structures can be seen at room temperature and can be exploited in real devices. All of the physics and devices that are based on properties of direct gap semiconductors near the center of the Brillouin zone. Quantum wells are one example of heterostructures–structures made by joining different materials, usually in layers, and with the materials joined directly at the atomic level. The chapter discusses only one class of effects, namely those related to optical absorption saturation near to the band-gap energy. The behaviour of the electro absorption for electric fields perpendicular to the quantum well layers is quite distinct from that in bulk semiconductors. The Self Electro-optic Effect Device principle is to combine a quantum well modulator with a photodetector to make an optically controlled device with an optical output.
