An ideal p-n junction germanium diode has a reverse saturation current of  at 300 K.

The voltage (in Volts, rounded off to two decimal places) to be applied across the junction to get a forward bias current of 100 mA at 300 K is _______.

(Consider the Boltzmann constant  and the charge of an electron .)

The photocurrent of a PN junction diode solar cell is . The voltage corresponding to its maximum power point is . If the thermal voltage is , the reverse saturation current of the diode (in , rounded off to two decimal places) is______.

A one-sided abrupt pn junction diode has a depletion capacitance  of  at a reverse bias of . The plot of  versus the applied voltage  for this diode is a straight line as shown in the figure below. The slope of the plot is __________ .

A pn junction solar cell of area , illuminated uniformly with , has the following parameters: Efficiency , open circuit voltage , fill factor , and thickness , The charge of an electron is . The average optical generation rate (in ) is

Which one of the following options describes correctly the equilibrium band diagram at T=300K of a Siliconconfiguration shown in the figure?

In an ideal pn junction with an ideality factor of 1 at T=300 K, the magnitude of the reverse-bias voltage required to reach 75% of its reverse saturation current, rounded off to 2 decimal places, is ___________mV.

A p-n step junction diode with a contact potential of 0.65 V has a depletion width of 1 pm at equilibrium. The forward voltage (in volts. correct to two decimal places) at which this width reduces to is _______

In a p-n junction diode at equilibrium_ which one of the following statements is NOT TRUE?

Red (R), Green (G) and Blue (b) Light Emitting Diodes (LEDs) were fabricated using p-n junctions of three different inorganic semiconductors having different band-gaps. The built-in voltages of red, green and blue diodes are and, respectively. Assume donor and acceptor doping to be the same (and, respectively) in the p and n sides of all the three diodes.

Which one of the following relationships about the built-in voltages is TRUE?

An  Silicon device is fabricated with uniform and non-degenerate donor doping concentrations of  and  corresponding to the and n regions respectively. At the operational temperature T, assume complete impurity ionization, kT/q = 25 mV, and intrinsic carrier concentration to be . What is the magnitude of the built-in potential of this device?

As shown, two Silicon (Si) abrupt p-n unction diodes are fabricated with uniform donor doping concentrations of  and in the n-regions of the diodes, and uniform acceptor doping concentrations of  in the p-regions of the diodes, respectively. Assuming that the reverse bias voltage is built-in potentials of the diodes, the ratio  of their reverse bias capacitances for the same applied reverse bias, is _________ .  

An abrupt pn junction (located at x = 0) is uniformly doped on both p and n sides. The width of the depletion region is W and the electric field variation in the x-direction is E(x). Which of the following figures represents the electric field profile near the pn junction?

Consider a silicon p-n junction with a uniform acceptor doping concentration of  on the p-side and a uniform donor doping concentration of  on the n-side. No external voltage is applied to the diode. Given: kT/q = 26 mV,  = 1.5 x  , = , = 8.85 ×  and q = 1.6 × . The charge per unit junction area (nC ) in the depletion region on the p-side is__________

Consider avalanche breakdown in a silicon  junction. The n-region is uniformly doped with a donor density. Assume that breakdown occurs when the magnitude of the electric field at any point in the device becomes equal to the critical field . Assume to be independent of. If the built-in voltage of the  junction is much smaller than the breakdown voltage, , the relationship between  and is given by

The I-V characteristics of the zener diodes D1 and D2 are shown in figure I. These diodes are used in the circuit given in figure II. If the supply voltage is varied from 0 to 100 V, then breakdown occurs

Consider the charges profile shown in the figure. The resultant potential distribution is best described by

A region of negative differential resistance is observed in the current voltage characteristics of a silicon PN junction if

The built-in potential of an abrupt p-n junction is 0.75 V. If its junction capacitance  at a reverse bias  of 1.25 V is 5 pF, the value of  (in pF) when = 7.25 V is ________.

For a silicon diode with long P and N regions, the accepter and donor impurity concentrations are 1 ×  and 1 ×  , respectively. The lifetimes of electrons in P region and holes in N region are both 100 µs. The electron and hole diffusion coefficients are 49  and 36 , respectively. Assume kT/q = 26 mV, the intrinsic carrier concentration is 1 × , and q = 1.6 × C. When a forward voltage of 208 mV is applied across the diode, the hole current density (in nA/) injected from P region to N region is _____________.

The doping concentrations on the p-side and n-side of a silicon diode are  and , respectively. A forward bias of 0.3 V is applied to the diode. At T = 300 K, the intrinsic carrier concentration of silicon  and . The electron concentration at the edge of the depletion region on the p-side is

Consider an abrupt PN junction (at T = 300 K) shown in the figure. The depletion region width  on the N-side of the junction is 0.2 µm and the permittivity of silicon () is . At the junction, the approximate value of the peak electric field (in kV/cm) is _________.

When a silicon diode having a doping concentration of  on p-side and  on n-side is reverse biased, the total depletion width is found to be 3 µm. Given that the permittivity of silicon is , the depletion width on the p-side and the maximum electric field in the depletion region, respectively, are

The donor and accepter impurities in an abrupt junction silicon diode are  and , respectively. Assume that the intrinsic carrier concentration in silicon  at 300 K,   and the permittivity of silicon . The built-in potential and the depletion width of the diode under thermal equilibrium conditions, respectively, are

The electric field profile in the depletion region of a p-n junction in equilibrium is shown in the figure. Which one of the following statements is NOT TRUE?

In a forward biased pn junction diode, the sequence of events that best describes the mechanism of current flow is

A silicon PN junction is forward biased with a constant current at room temperature. When the temperature is increased by , the forward bias voltage across the PN junction

A Zener diode, when used in voltage stabilization circuits, is biased in

Compared to a p-n junction with , which one of the following statements is TRUE for a p-n junction with ?

Consider a silicon p-n junction at room temperature having the following parameters:

Doping on the n-side

Depletion width on the n-side

Depletion width on the p-side

Intrinsic carrier concentration

Thermal voltage = 26 mV

Permittivity of free space

Dielectric constant of silicon = 12

The built-in-potential of the junction

Consider a silicon p-n junction at room temperature having the following parameters:

Doping on the n-side

Depletion width on the n-side

Depletion width on the p-side

Intrinsic carrier concentration

Thermal voltage = 26 mV

Permittivity of free space

Dielectric constant of silicon = 12

The peak electric field in the device is

Which of the following is NOT associated with a p-n junction?

Consider the following assertions.

S1: For Zener effect to occur, a very abrupt junction is required.

S2: For quantum tunnelling to occur, a very narrow energy barrier is required.

Which of the following is correct?

In a n junction diode under reverse bias, the magnitude of electric field is maximum at

A  junction has a built-in potential of 0.8 V. The depletion layer width at a reverse bias of 1.2V is 2μm. For a reverse bias of 7.2V, the depletion layer width will be

Group I lists four types of p-n junction diodes. Match each device in Group I with one of the options in Group II to indicate the bias condition of that device in its normal mode of operation.

The values of voltage across a tunnel-diode corresponding to peak and valley currents are  and  respectively. The range of tunnel-diode voltage  for which the slope of its  characteristics is negative would be

In the circuit shown below, the switch was connected to position 1 at t < 0 and at t = 0, it is changed to position 2. Assume that the diode has zero voltage drop and a storage time. For,is given by (all in Volts)

Find the correct match between Group 1 and Group 2:

A silicon PN junction at a temperature of has a reverse saturation current of 10 pico-Amperes (pA).

The reverse saturation current at  for the same bias is approximately

A silicon PN junction diode under reverse bias has depletion region of width, the relative permittivity of silicon,  and the permittivity of free space. The depletion capacitance of the diode per square meter is

In an abrupt p-n junction, the doping concentrations on the p-side and n-side are  and  respectively. The p-n junction is reserve biased and the total depletion width is 3μm. The depletion width on the p-side is

Consider an abrupt p-junction. Let  be the built-in potential of this junction and be the applied reverse bias. If the junction capacitance  is 1 pF for , then for ,  will be

Choose proper substitutes for X and Y to make the following statement correct Tunnel diode and Avalanche photodiode are operated in X bias and Y bias respectively.

Match items in Group 1 with items in Group 2, most suitably

At 300 K, for a diode current of 1mA, a certain germanium diode requires a forward bias of 0.1435V, whereas a certain silicon diode requires a forward bias of 0.718V. Under the conditions stated above, the closest approximation of the ratio of reverse saturation current in germanium diode to that in silicon diode is

A particular green LED emits light of wavelength 5490ºA. The energy band-gap of the semiconductor material used there is

(Plank’s constant =)

In Figure a silicon diode is carrying a constant current of 1 mA. When the temperature of the diode is 20ºC,  is found to be 700 mV. If the temperature rises to 40ºC,  becomes approximately equal to

The static characteristic of an adequately forward biased p-n junction is a straight line, if the plot is of

The p-type substrate in a conventional pn-junction isolated integrated circuit should be connected to

The diffusion potential across a P-N junction

A zener diode works on the principle of

The depletion capacitance, , of an abrupt P-N junction with constant doping on either side varies with reverse bias, , as

The built-in potential (Diffusion potential) in a p-n junction        

A P-N junction in series with a 100 ohms resistor is forward biased so that a current of 100mA flows. If the voltage across this combination is instantaneously reversed to 10 V at, the reverse current that flows through the diode at  is approximately given by

An infrared LED is usually fabricated from        

The small signal capacitances of an abrupt  junction is  at zero bias. If the built in voltage is 1 volt, the capacitance at a reverse bias voltage of 99 volts is equal to __

Referring to the figure. The switch S is in position 1 initially and steady state conditions exist from time  to . The switch is suddenly thrown into position 2. The current I through the 10K resistor as a function of time t from , is ….. (Give the sketch showing the magnitudes of the current at ,  and )

The current I in a forward biased  junction shown in figure (a) is entirely due to diffusion of holes from  and . The injected hole concentration distribution in the n-region is linear as shown in figure (b), with  and .

Determine:

(a) The current density in the diode, assuming that the diffusion coefficient of holes is

(b) The velocity of holes in the n-region at.