Question

Given a Ternary compound, GaAs1-xPx, what value of x in the formula that would yield the ratio that would result in the following colours: (i) Infrared (ii) Green [8 marks]

A si crystal is to be grown by the Czochralski method and it is desired that the ingot contain phosphorus atoms/cm³. [For P in Si, Ka 0.35, Atomic weight of phosphorus is 31, density of Si 2.33g/cm³, Avogadro's no. 6.02 x 10²³ atom/mole]
(c) What concentration of phosphorus atoms should the melt contain to give this impurity concentration in the crystal during the initial growth? If the initial load of Si in the crucible is 5Kg, how many grams of phosphorus should be added?

Answer 1

To achieve infrared color, we need to increase the value of x, and to achieve green color, we need to decrease the value of x.

Step-by-step explanation:

To determine the value of x in the formula GaAs1-xPx that would yield a specific color, we need to know the values of x for each color. Let's consider the two colors mentioned:

(i) Infrared: Infrared light has a longer wavelength and lower energy compared to visible light. It is typically associated with longer-wavelength electromagnetic radiation. To achieve infrared color, we need to increase the value of x, which means increasing the concentration of the compound GaAs1-xPx.

(ii) Green: Green light has a wavelength between approximately 520 and 570 nanometers. To achieve green color, we need to decrease the value of x, which means decreasing the concentration of the compound GaAs1-xPx.

Without specific values of x, we cannot determine the exact concentrations required for the desired colors.