What is the optimum band gap energy for a material to be considered as a semiconductor?

Hint: Semiconductor materials have less but measurable band gap energy, due to which there is a comfortable jump of an electron from the valence to the conduction band in the provision of outer thermal energy.

Complete answer:
Wide-bandgap semiconductors are semiconductor substances with a larger band gap than traditional semiconductors. Traditional semiconductors like silicon have an energy band gap on the scale of $1 - 1.5$ electron volt (eV), whereas wide-bandgap elements have bandgaps in $2 – 4$ eV. Generally, wide-bandgap semiconductors have electric properties which fall in among those of traditional semiconductors and insulators.
Wide-bandgap semiconductors approve devices to operate at much greater voltages, frequencies, and temperatures than traditional semiconductor substances like silicon and gallium arsenide. They are the critical component used to create green and blue LEDs and lasers and are also utilized in specific radio frequency uses distinctly military radars. Their intrinsic qualities execute them suitable for a broad range of other applications, and they are one of the front contenders for next-generation materials for general semiconductor application.
Most wide-bandgap elements also have high free-electron speeds, enabling them to work at more incredible switching speeds, adding to their value in wireless applications. In addition, a single WBG device can be utilized to make a whole radio system, dropping the need for separate signal and radio-frequency elements while working at greater frequencies and power levels.
The average scale of band gap energy for a semiconductor substance is $0.5eV−3eV$.

Note: The wider bandgap is especially important for supporting devices that use them to work at much larger temperatures. This makes them highly attractive for service applications, where they have noticed a fair amount of utility. The high-temperature limit also means that these devices can be performed at much greater power levels under ordinary conditions. Additionally, most wide-bandgap elements also have a tremendous critical electrical field density, on the multiple of ten times that of traditional semiconductors.