A quantum well is a thin layer of semiconductor material where charge carriers, such as electrons, are confined in a very small space. This confinement occurs in one dimension, allowing the carriers to move freely in the other two dimensions. The result is quantized energy levels, meaning the electrons can only occupy specific energy states. Quantum wells are essential in various electronic and optoelectronic devices. These structures are commonly used in laser diodes, light-emitting diodes (LEDs), and photodetectors. By manipulating the thickness of the quantum well and the materials used, engineers can tailor the properties of these devices, such as their emission wavelength and efficiency.