Question

20. Vegard's law states that: A. the lattice constant of an alloy is linearly dependent on the lattice constants of its constituents B. the energy bandgap of an alloy is linearly dependent on the energy bandgaps of its contituents C. the energy bandgap of an alloy is non-linearly dependent on the energy bandgaps of its contituents D. none of the above 21. What is the typical internal quantum efficiencies of InGaN lightemitting diodes? A. 10 to 20% B. 30 to 40% C. 50 to 60% D. 70 to 80% 22. Which of the following materials is least suitable of the packaging of light-emitting diode chips? A. ceramic B. plastic C. copper D. aluminum

Answer 1

Vegard's law states that the lattice constant of an alloy is linearly dependent on the lattice constants of its constituents. InGaN light-emitting diodes have typical internal quantum efficiencies of around 70 to 80%. Aluminum is the least suitable material for packaging light-emitting diode chips.

Step-by-step explanation:

Vegard's law states that the lattice constant of an alloy is linearly dependent on the lattice constants of its constituents. In other words, the lattice constant of an alloy can be determined by taking a weighted average of the lattice constants of its constituent elements. This law is often used in materials science to predict the properties of alloys.

The typical internal quantum efficiencies of InGaN light-emitting diodes (LEDs) are around 70 to 80%. Internal quantum efficiency refers to the ratio of the number of photons emitted by the LED to the number of electrons injected into the device. InGaN LEDs have high internal quantum efficiencies, making them efficient light sources.

In terms of packaging of light-emitting diode chips, ceramic, plastic, and copper are commonly used materials. However, aluminum is often considered the least suitable material for packaging LED chips due to its poor thermal conductivity and limited compatibility with LED chip technology.