Optoelectronic Devices

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JEE Main 2021

LED is constructed from GaAsP semiconducting material. The energy gap of this LED is $1.9 eV$ . Calculate the wavelength of light emitted and its colour. [ $h = 6.63 \times 1 0^{- 34} Js$ and $c = 3 \times 1 0^{8} ms^{- 1}$ ]

1046 nm

and red colour

(B)

654 nm

and orange colour

(C)

1046 nm

and blue colour

(D)

654 nm

and red colour

JEE Main 2021

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Consider a situation in which reverse biased current of a particular p-n junction increases when it is exposed to a light of wavelength $\leq 621$ nm. During this process, enhancement in carrier concentration takes place due to generation of hole-electron pairs. The value of band gap is nearly

Identify the semiconductor devices whose characteristics are as given below, in the order (a), (b), (c), (d).

(A)

Simple diode, Zener diode, Solar cell, Light dependent resistance

(B)

Zener diode, Simple diode, Light dependent resistance, Solar cell

(C)

Solar cell, Light dependent resistance, Zener diode, Simple diode

(D)

Zener diode, Solar cell, Simple diode, Light dependent resistance

JEE Main 2020

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With increasing biasing voltage of a photodiode, the photocurrent magnitude

(A)

increases initially and after attaining certain value, it decreases

(B)

increases initially and saturates finally

If a semiconductor photodiode can detect a photon with a maximum wavelength of $400 nm$ , then its band gap energy is (Take, Planck's constant, $h = 6.63 \times 1 0^{- 34} J-s$ and speed of light, $c = 3 \times 1 0^{8} m/s$ )

(A)

1.5 eV

(B)

1.1 eV

(C)

3.1 eV

(D)

2.0 eV