Given below are two statements : Statement I : In case a reverse biased photodiode is kept in a open light, the current flowing through the device corresponds to value of reverse saturation current. Statement II : Photovoltaic emf of semiconductor photodiode is that voltage at which the resultant current flowing the device becomes zero. In the light of the above statement, choose the most appropriate answer from the options given below :
Statement I is incorrect but Statement II is correct
Let's analyze the given statements regarding the behavior of a photodiode:
- Statement I: "In case a reverse biased photodiode is kept in an open light, the current flowing through the device corresponds to the value of reverse saturation current."
- A photodiode, when reverse biased and exposed to light, generates a photocurrent due to the electron-hole pairs created by the incident light. The total current in the photodiode is a combination of the thermally generated saturation current and the light-generated photocurrent.
- The reverse saturation current is the small current that flows due to minority carriers at reverse bias when no light is present. However, when light is present, the photocurrent adds to this, making the total current higher than just the reverse saturation current.
- Thus, the statement is incorrect because the current under illumination is not just the reverse saturation current; it includes an additional photocurrent component.
- Statement II: "Photovoltaic emf of a semiconductor photodiode is that voltage at which the resultant current flowing through the device becomes zero."
- In a photodiode under illumination, the photovoltaic effect generates a voltage opposite to the current flow direction. At this point, the photocurrent compensates the reverse saturation current, resulting in zero net current.
- This condition occurs when the photodiode is open-circuited, and the internally generated emf (photo-voltage) balances the reverse saturation current.
- Therefore, this statement is correct as it describes the open-circuit condition accurately.
Conclusion: Based on the analysis above, Statement I is incorrect because it doesn't consider the additional photocurrent under illumination, while Statement II correctly explains the condition of photovoltaic emf. Thus, the correct answer is: Statement I is incorrect but Statement II is correct.
Similar Questions
Consider the following statements for photo diode (PD) and Avalanche Photo Diode (APD)
A. The response time of APD is larger than PD
B. Photo current is a diffusion current for PD and APD
C. APD can handle greater amount of power in comparison to PD
D. Photo current is a minority carrier current for PD and APD
E. compare to ordinary pn diode, power handling capacity of PD is higher.
Choose the correct answer from the options given below :
In a p-i-n photodiode the depletion region thickness can be tailored to
(a) optimize the quantum efficiency
(b) optimize the frequency response
(c) optimize the quantum efficiency but not the frequency response.
(d) optimize the frequency response but not the quantum efficiency.
Out of these
In case a reverse biased photodiode is kept in dark condition, the current flowing through the device corresponds to:
Assertion (A) : Those semiconductor materials that have practically no thermally generated current carriers at room temperature are used as photoconductors.
Reason (R) : These materials are essentially insulators in the dark and carriers generated by the absorption of light cause maximum possible change in the resistivity of the cell.
Select your answer using the codes given below.
Assertion (A) : In PIN photodiodes, an intrinsic layer is there, which is slightly doped with n type material.
Reason (R) : It disables us to increase the width of the depletion region to a value which is far lesser what it could be in a PN diode.
Select your answer using the codes given below.
Photodiode can be used as :
(a) as a detector in forward biased
(b) as a detector in reverse biased
(c) as an LDR
(d) it generates solar energy
Which of the above statements are correct ?
The carrier velocity in a silicon p-i-n photodiode with 25 μm depletion layer width is 3 × 104 m/s. The maximum response time for the pin diode is given by :
Consider the following statements :
(A) The charge coupled device (CCD) is a linear scanning system
(B) The charge coupled device is a non linear scanning system
(C) A charge coupled devices is used as a shift register
(D) A charge coupled device can not be used as a photo detectorChoose the most appropriate answer from the options given below :
Important Questions from Photodetectors - Teaching
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: In a photodetector, it is desired that the width of the depletion region W be large enough so that most of the photons are absorbed within W rather than in the neutral n and p regions.
Reason R: A wider width W results in small junction capacitance.
In the light of the above statements, choose the most appropriate answer from the options given below
Consider the following statements for photo diode (PD) and Avalanche Photo Diode (APD)
A. The response time of APD is larger than PD
B. Photo current is a diffusion current for PD and APD
C. APD can handle greater amount of power in comparison to PD
D. Photo current is a minority carrier current for PD and APD
E. compare to ordinary pn diode, power handling capacity of PD is higher.
Choose the correct answer from the options given below :
In a p-i-n photodiode the depletion region thickness can be tailored to
(a) optimize the quantum efficiency
(b) optimize the frequency response
(c) optimize the quantum efficiency but not the frequency response.
(d) optimize the frequency response but not the quantum efficiency.
Out of these
In case a reverse biased photodiode is kept in dark condition, the current flowing through the device corresponds to:
Assertion (A) : Those semiconductor materials that have practically no thermally generated current carriers at room temperature are used as photoconductors.
Reason (R) : These materials are essentially insulators in the dark and carriers generated by the absorption of light cause maximum possible change in the resistivity of the cell.
Select your answer using the codes given below.
