Question

Which semiconductors are preferred to make LEDs and why?

Answer 1

Semiconductors with appropriate band gap (Eg) close to 1.5 eV are preferred to make LED size GaAs, CdTe, etc.the other reasons to select these materials e high optical absorption, availability of raw material and low cost

Answer 2

Most Common examples are; GaAs ,CdTe, etc.

Explanation:

Semi-Conductors with a heavily doped forward-biased p-n junction having a band-gap of Energy 1.5eV are the most appropriate choices to make the LED.  

Most Common examples are, GaAs ,CdTe, etc.

This is done because of p-n junctions having better optical properties such as higher optical absorption, less power consumption.  

Moreover, the commonly used i.e. GaAs, CdTe are very easily available and cheap. and so are p-n junctions to make.