- Why band gap of silicon is more than germanium?
- What is the best diode for a crystal radio?
- Why do band gaps exist?
- Why germanium controlled rectifier is not possible?
- What is a germanium diode?
- What is forbidden energy gap?
- How can you tell if a diode is silicon or germanium?
- What is the difference between silicon and germanium?
- Why leakage current is more for germanium diode?
- What is silicon diode?
- How do you identify a Schottky diode?
- What is diode leakage current?
- Which diode is better silicon or germanium?
- Why is Germanium a semiconductor?
- What is the use of silicon and germanium?
- What are Schottky diodes used for?
- Why is band gap important?
- What is the reverse current of a diode?
Why band gap of silicon is more than germanium?
Look at the periodic table, you’ll see that germanium is under silicon, and hence has an extra shell (higher principal quantum number) due to it having a higher atomic number (more electrons).
Silicon’s valence orbital is 3p2, while germanium is 4s2..
What is the best diode for a crystal radio?
The 1N34A germanium diode is the modern substitute for galena and most other germanium small-signal diodes will also work well. Silicon diodes are not a good choice because their much higher barrier potential requires larger signals for efficient rectification.
Why do band gaps exist?
Why bands and band gaps occur When the atoms are far apart (right side of graph) each atom has valence atomic orbitals p and s which have the same energy. … At that spacing the orbitals form two bands, called the valence and conduction bands, with a 5.5 eV band gap between them.
Why germanium controlled rectifier is not possible?
Ability to withstand at high temperature: silicon crystals have capability to withstand at higher temperature compare to germanium crystals . So if leakage current is produced in SCR it heats up the device then silicon crystals can withstand but not germanium crystals.
What is a germanium diode?
A germanium diode is a diode made using the element Germanium in stead of Silicon (Silicium). While both perform the same function (they only let current pass through them in one direction) there are some differences between the silicon and germanium variants. The most obvious is the forward bias voltage.
What is forbidden energy gap?
Forbidden gap The gap between valence band and conduction band is called as forbidden energy gap. As the name implies, this band is the forbidden one without energy. Hence no electron stays in this band.
How can you tell if a diode is silicon or germanium?
The general rule is that SILICON diodes have a voltage drop across the Anode to Cathode of 0.7 V (7/10 tenths), and the GERMANIUM diodes have a voltage drop of 0.3 V (3/10 tenths) more or less. Either diode voltage drop (silicon or germanium) will display a reading within approximately 5% of these readings.
What is the difference between silicon and germanium?
The key difference between silicon and germanium is that the Germanium has d electrons, but Silicon does not have any d electrons. Silicon and germanium, are both in the same group (group 14) of the periodic table. … Silicon and germanium share similar physical and chemical characteristics since both are metalloids.
Why leakage current is more for germanium diode?
Much of the leakage current is due to surface conduction, related to the lack of cleanliness of the semiconductor surface. Both leakage currents increase with increasing temperature, approaching a µA for small silicon diodes. For germanium, the leakage current is orders of magnitude higher.
What is silicon diode?
A diode is an electrical switch commonly made of semiconductor material, such as silicon. It consists of two terminals: positive (anode) and negative (cathode). It is often used as a rectifier, which is a device that converts AC to DC with current flowing in one direction.
How do you identify a Schottky diode?
The Schottky diode is measured in both forward And reverse directions. If the re a, the measurement in Figure 8-25 indicates that the tube is a silicon diode. If it is a germanium diode, the forward voltage reading should be less than 0.3V.
What is diode leakage current?
When a diode is reverse biased, the width of the depletion region increases. … It is seen that in a reverse-biased diode, some current flows through the depletion region. This current is called leakage current. Leakage current is dependent on minority current carriers.
Which diode is better silicon or germanium?
The structure of Germanium crystals will be destroyed at higher temperature. However, Silicon crystals are not easily damaged by excess heat. Peak Inverse Voltage ratings of Silicon diodes are greater than Germanium diodes. Si is less expensive due to the greater abundance of element.
Why is Germanium a semiconductor?
Germanium atoms have one more shell than silicon atoms, but what makes for the interesting semiconductor properties is the fact that both have four electrons in the valence shell. As a consequence, both materials readily constitute themselves as crystal lattices. Substituted atoms alter the electrical properties.
What is the use of silicon and germanium?
Silicon-germanium is an important material that is used for the fabrication of SiGe heterojunction bipolar transistors and strained Si metal-oxide-semiconductor (MOS ) transistors for advanced complementary metal-oxide-semiconductor (CMOS ) and BiCMOS (bipolar CMOS) technologies.
What are Schottky diodes used for?
Schottky diodes are used for their low turn-on voltage, fast recovery time and low-loss energy at higher frequencies. These characteristics make Schottky diodes capable of rectifying a current by facilitating a quick transition from conducting to blocking state.
Why is band gap important?
A band gap is the distance between the valence band of electrons and the conduction band. Essentially, the band gap represents the minimum energy that is required to excite an electron up to a state in the conduction band where it can participate in conduction.
What is the reverse current of a diode?
Zero Biased Junction Diode This is known as the “Reverse Current” and is referenced as IR. This transfer of electrons and holes back and forth across the PN junction is known as diffusion, as shown below.