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What is difference between silicon and germanium semiconductors?
Silicon has a larger bandgap energy than germanium, which contributes to higher junction potentials and ability to operate at higher temperatures.
What property do you use to classify materials into three states?
Bandgap
What are the indirect bandgap materials?
GaP in an indirect band gap material
Is germanium reactive?
germanium reacts naturally
What is the atomic symbol of germanium?
Germanium is Ge.
Why we can't use silicon and germanium in laser diode?
becoz Si and Ge are indirect bandgap semiconductors. for lasing action direct bandgap semiconductors are required of the type In Ga As P
What is difference between silicon and germanium semiconductors?
Silicon has a larger bandgap energy than germanium, which contributes to higher junction potentials and ability to operate at higher temperatures.
What is importance of band gap in semiconductors?
bandgap has an importance role for conduction.if bandgap is max,the conduction of electron is min. and vice-versa.hence we can say that the bandgap desides the conductivity of any material(may be metal or nonmetal)
Why the voltage drop across LED is around 2V instead of 0.7V?
the binary semiconductors used to make LEDs have forward bias voltages from 1.5V to 6V depending on color (1.5V for IR-red to 6V for blue-UV) because the bandgap voltage of the semiconductor is higher than silicon. This higher bandgap is where the photons generated get their energy from. germanium has a lower forward bias voltage of 0.2V because the bandgap voltage is lower. metal-semiconductor contacts, like point contact diodes and schottky barrier diodes, can have forward bias voltages under 0.1V
Advantages of silicon over germanium?
silicon has a wider bandgap than germenium .silicon jeakage current small, easily available then Ga and break down voltage is more. knee voltage of si is 0.7and Ga is having 0.3then Si is very useful.
What is bifference between optical bandgap and semiconduct0r bandgap?
we all know that electrons,photons, phonons can excite an electron from valence band to conduction band...i think the main difference between electronic bandgap and optical bandgap is that in electonic its the energy required for an electron to move from the valence band to the conduction band.but in optical bandgap photons(packet of energy in the form of light waves) are assisting the electrons to move from valence band to conduction band.The difference between optical and electronic bandgap is more complexe actually. The optical bandgap is the one that can be measured using optical techniques (based on transmission and reflection, i.e. Tauc plot). However, this measurement does not take into account all traps you might have within the bandgap that can modify the energy required to move one charge carrier from the conduction band ans the conduction band. The electronic band gap (which is the one of interest in fine, in an integrated device) is measured under operation. Thus, for many devices (lasers, solar cells...etc.) the electronic bandgap (energy required to get the device working) can defer from the optical bandgap.
Why the LED emitting light but P-N junction diodes are not?
LEDs are built from binary semiconductors like: gallium arsenide phosphide (GaAsP) for red, aluminium gallium indium phosphide (AlGaInP) for green, silicon carbide (SiC) for blue, etc. instead of the silicon or germanium used in ordinary junction diodes. This has the following effects:when electrons and holes recombine at the P-N junction of an LED the bandgap is large enough to produce visible light photons, but in silicon and germanium the bandgap is only large enough to produce far infrared photonsthe binary semiconductors used to make LEDs are transparent to visible light so the photons produced escape the device, silicon and germanium are opaque and immediately absorb the far infrared photons they produce which only heats the device slightly
What is the definition of optical and electrical bandgap?
Optical bandgap means bandgap estimated using optical means or characterization. In simple words, let a light of different energies incident on the material. The material absorbs some energies and transmits some energies (the detector measures this). The threshold energy at which the material starts absorbing light is "Optical Bandgap". In a similar manner, electrical bandgap means bandgap estimated using electrical means or characterization. Here instead of measuring what light is observed of transmitted. You make electrical contacts for the material and measure the current instead of optical absorption. The incident light is of course absorbed, and carriers (electrons and holes) are generated in proportion to absorption. We measure current (nothing but charge which is proportional to absorption) and this current too shoots up at a threshold energy i.e. electrical bandgap.
What property do you use to classify materials into three states?
Bandgap
Is germanium toxic?
Germanium compounds are toxic.
What are the indirect bandgap materials?
GaP in an indirect band gap material
What does germanium do?
Germanium does no "do" anything.
