OPTOELECTRONIC AND PHOTOVOLTAIC DEVICES

Elementary quantum mechanics. Heterostructures. Anderson theory for band alignment. Band diagrams. Capacitance-voltage profiling. Quantum wells. Compound semiconductor devices, heterojunctions and their properties. Heterostructure Field Effect Transistors and their applications. Modulation doping and High Electron Mobility Transistors (HEMTs); applications to 5G telecommunication infrastructure and to power electronics. Optical properties of semiconductors. Radiative transitions, light absorption; rate equations. Non-radiative recombination, Auger recombination. Theory of radiative recombination in semiconductors. Light-emittin devices, Light Emitting Diodes (LED). Current-voltage LED characteristics. Non-ideality of I-V characteristics, parasitic resistances. Carrier loss and carrier overflow; electron blocking layers: case histories, efficiency droop. Dependence on temperature of electrical and optical characteristics. Internal and external quantum efficiency, extraction efficiency. High efficiency LEDs. Semiconductor lasers: conditions for laser oscillation, gain threshold voltage.
Mode propagation in the optical cavity. Laser diodes operating principles. Steady-state rate equations. Optical power vs current laser characteristics. Semiconductor lasers for optical fiber communications. Superluminescent diodes. Photodetectors: pin diodes, avalanche photodetectors (APD), Metal Semiconductor Metal detectors (MSM), fototransistors. Solar cells: structure, operating principles, deviations from ideality. Optimized structures for solar cells: multijunction cells, thin film photovoltaic devices. Solar concentration. Reliability in optoelectronics, assignment of master thesis topics.