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Which of the following correctly represents the increasing order of band gap energy at room temperature?
Ge < Si < GaAs
Si < Ge < GaAs
GaAs < Si < Ge
Ge < GaAs < Si
Ge < Si < GaAs
The band gap energy (EgтАЛ) of a semiconductor is the minimum energy required to excite an electron from the valence band to the conduction band. At room temperature (300┬аK), Ge has the smallest band gap, followed by Si, and GaAs, which is a compound semiconductor, has the largest among the three.
The band gap energy (EgтАЛ) of a semiconductor is the minimum energy required to excite an electron from the valence band to the conduction band. At room temperature (300┬аK), Ge has the smallest band gap, followed by Si, and GaAs, which is a compound semiconductor, has the largest among the three.
EgтАЛ(T)тЙИEgтАЛ(0)тИТT+╬▓╬▒T2тАЛ тАФ (Varshni relation for temperature dependence of band gap)
E=╬╗hcтАЛ тАФ (Relation between photon energy and wavelength corresponding to the band gap)
The band gap depends on the atomic structure and the strength of the atomic bonding. Elements like Ge and Si belong to Group IV, while GaAs is a III-V compound semiconductor; the compound semiconductors generally exhibit larger band gaps due to the differences in electronegativity and lattice potential between the constituent atoms.
Band gap of Germanium (Ge) is approximately 0.67┬аeV at room temperature.
Band gap of Silicon (Si) is approximately 1.12┬аeV at room temperature.
Band gap of Gallium Arsenide (GaAs) is approximately 1.42┬аeV at room temperature.
Semiconductors with higher band gaps are preferred for high-temperature applications.
Higher band gap materials (like GaAs) allow operation at higher temperatures.
Larger band gap facilitates high-frequency operation and optical applications.
Materials with larger band gaps often have higher manufacturing complexity and cost.
Lower band gap materials are more sensitive to thermal noise.
Silicon is standard for integrated circuits and microprocessors.
GaAs is extensively used in high-speed communication and optoelectronic devices like LEDs and laser diodes.
The values are specifically 0.67┬аeV for Ge, 1.12┬аeV for Si, and 1.42┬аeV for GaAs.
Option B, C, and D are incorrect because they violate the established experimental measurements of the forbidden energy gap for these materials.
A is correct тАФ The band gap energy values at room temperature follow the order 0.67┬аeV┬а(Ge)<1.12┬аeV┬а(Si)<1.42┬аeV┬а(GaAs).
Always remember the simple mnemonic: Ge (0.7) < Si (1.1) < GaAs (1.4). Understanding these specific values helps significantly in both Physics and Electronic Device papers.
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