Photodiode Detectors
A silicon photodiode is configured as shown in Fig. 14-18 with a 90 V bias voltage. The light to be detected has intensity 20 _W/cm2 and wavelength 920 nm. Relevant material properties for the detector are: absorption efficiency = 0.18, dark current density at room temperature = 15 nA/cm2, charge carrier mobility = 0.048 m2/Vs, and carrier saturation velocity = 105 m/s. At the applied bias voltage, it is known that the width of the depletion region is 0.2 mm. (a) If the photocurrent is 150 nA, what is the area of the detector? (b) If the load resistor is 100 k_, determine the RC time constant of the circuit, and the corresponding 3 dB bandwidth. Video requires a bandwidth of about 2 MHz. Will the circuit be suitable for video applications? (c) Determine the transit-time response for the circuit, and compare it with the RC time constant. Which is the primary limit to the bandwidth in this circuit? (d) Repeat part b assuming a load resistance of 10 k_. Is the circuit now suitable for video applications?
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Photodiode Detectors
A silicon p–n junction photodiode has junction area 1 cm2, and doping levels 1014 and 1016 cm–3 on the n and p sides, respectively. It is reverse biased with 15 V and a 10 k_ load resistor is used. (a) Determine the 3 dB electrical bandwidth due to the RC time constant. (b) Determine the bandwidth due to the hole transit time. (c) What is the limiting bandwidth in this case?
Photodiode Detectors
Assume the total response time of a silicon photodiode can be taken as the sum of the transit time (limited by saturation velocity 105 m/s) and the RC rise time tr. Derive an expression for the optimum intrinsic region thickness d. If the load resistance is 50 _ and the detector area is 0.01 mm2, calculate d and the resulting detector bandwidth.
Photodiode Detectors
14.1 A photodiode with responsivity 0.3 A/W and dark current 2 nA is biased in the photoconductive mode, with a 9 V battery and 500 k_ resistor. Make a sketch like that of Fig. 14-3, showing the load line and the diode curves for incident powers from zero to 100 _W in steps of 20 _W. Circle the operating point for an incident power of 40 _W, and determine the approximate diode voltage from the graph.
Photodiode Detectors
A high-speed germanium PIN photodiode has a depletion width of 10 _m and a reverse-bias voltage of 10 V. The hole mobility in Ge is _ 0.2 m2/(Vs), the saturation velocity is _ 7 × 104 m/s, and the refractive index at 1300 nm is _ 4.3. (a) Determine the transit time limit to the response time, and calculate the corresponding 3 dB electrical bandwidth. (b) If light of wavelength 1300 nm is detected, determine the fraction of incident light...
photodiode
Assume that the total time response of a vacuum photodiode is given by the sum ofthe transit time and the RC time constant. (a) Derive an expression for the plateseparation d that minimizes the total response time. Put your answer in terms of theapplied voltage V0, the plate area A, and the load resistor R. (b) Calculate this optimumplate separation for parallel plates of diameter 2 cm, a voltage 2.5 kV, and aload resistance 50 _. Repeat for a load...
An important application of PN diodes is their use as photodetectors. The optical radiation creates electron-hole...
An important application of PN diodes is their use as photodetectors. The optical radiation creates electron-hole pairs in the depletion region and regions within the diffusion lengths near the depletion edges. These e-h pairs are collected as a photocurrent. The e-h pairs are generated at the rate GL 1022 cm-3s1. Calculate the photocurrent. Consider a silicon PN diode at 300K with following parameters Equation for photocurrent calculation: AGL (W Ln Lp) A 104 um2 Na = 2 x 1016 cm-3...
Problem 1 Using what we have leamed in chapter 1, derive, for a semiconductor, the expressions of...
Problem 1 Using what we have leamed in chapter 1, derive, for a semiconductor, the expressions of The total current density Conductivity - Problem 2 Consider Germanium sample with the following characteristics the electron and hole mobility for Ge is 0.39 and 0.19 m2N.s The electron and hole effectives masses are 0.56me and 0.4 me The energy gap is 0.67 eV at T-27°C 1) 2) Find the intrinsic carrier concentration for Ge What is the resistivity of the Ge sample...
Taking pure silicon (Si) as an example, explain what is meant by the terms electron-hole generation...
Taking pure silicon (Si) as an example, explain what is meant by the terms electron-hole generation and recombination, how they affect the electrical conductivity, and define what is meant by the "intrinsic carrier density", n. [5 marks] Q3. a) b) With the aid of both lattice and energy band diagrams, explain how n-type doping of Si is achieved and state two types of suitable dopant atoms. [7 marks] c) An n-type region on a Si wafer has a donor concentration...
summatize the following info and break them into differeng key points. write them in yojr own...
summatize the following info and break them into differeng key points. write them in yojr own words
apartus
6.1 Introduction—The design of a successful hot box appa- ratus is influenced by many factors. Before beginning the design of an apparatus meeting this standard, the designer shall review the discussion on the limitations and accuracy, Section 13, discussions of the energy flows in a hot box, Annex A2, the metering box wall loss flow, Annex A3, and flanking loss, Annex...
An important application of PN diodes is their use as photodetectors. The optical radiation creates electron-hole pairs in the depletion region and regions within the diffusion lengths near the depletion edges. These e-h pairs are collected as a photocurrent. The e-h pairs are generated at the rate GL 1022 cm-3s1. Calculate the photocurrent. Consider a silicon PN diode at 300K with following parameters Equation for photocurrent calculation: AGL (W Ln Lp) A 104 um2 Na = 2 x 1016 cm-3...
Problem 1 Using what we have leamed in chapter 1, derive, for a semiconductor, the expressions of The total current density Conductivity - Problem 2 Consider Germanium sample with the following characteristics the electron and hole mobility for Ge is 0.39 and 0.19 m2N.s The electron and hole effectives masses are 0.56me and 0.4 me The energy gap is 0.67 eV at T-27°C 1) 2) Find the intrinsic carrier concentration for Ge What is the resistivity of the Ge sample...
Taking pure silicon (Si) as an example, explain what is meant by the terms electron-hole generation and recombination, how they affect the electrical conductivity, and define what is meant by the "intrinsic carrier density", n. [5 marks] Q3. a) b) With the aid of both lattice and energy band diagrams, explain how n-type doping of Si is achieved and state two types of suitable dopant atoms. [7 marks] c) An n-type region on a Si wafer has a donor concentration...
summatize the following info and break them into differeng key points. write them in yojr own words
apartus
6.1 Introduction—The design of a successful hot box appa- ratus is influenced by many factors. Before beginning the design of an apparatus meeting this standard, the designer shall review the discussion on the limitations and accuracy, Section 13, discussions of the energy flows in a hot box, Annex A2, the metering box wall loss flow, Annex A3, and flanking loss, Annex...
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