What are common applications of semiconductors in opto-electronics?

The correct answer includes light sources, photodetectors, and solar cells, which are all essential applications of semiconductors in the field of opto-electronics.

Light sources, such as light-emitting diodes (LEDs) and laser diodes, are critical for various applications like lighting, displays, and communication devices. Photodetectors, which include photodiodes and phototransistors, are used to sense and convert light into an electrical signal, playing a vital role in cameras, optical sensors, and fiber-optic communication. Additionally, solar cells are pivotal in converting sunlight into electricity, making them integral to renewable energy technologies.

This answer encapsulates a broader range of applications than the other options, which are limited in scope. The other choices focus narrowly on a single application area, failing to recognize the diverse functionality of semiconductors across various opto-electronic devices.