Electronics Devices And Circuit 1(TTA)

n-type semiconductors are produced when Phosphorous is added as an impurity to Silicon. This is because Phosphorous has five valence electrons, while Silicon has four. When Phosphorous is added to Silicon, the extra electron becomes a free electron that is able to move freely within the crystal lattice. This creates an excess of negatively charged electrons, giving the semiconductor an overall negative charge. Therefore, the correct answer is "Produced when Phosphorous is added as an impurity to Silicon."

When a diode is forward-biased, the recombination of free electrons and holes may produce heat, light, and radiation. This is because when the diode is forward-biased, the p-n junction allows the flow of current in the forward direction. During this process, free electrons and holes combine, releasing energy in the form of heat. Additionally, depending on the energy level of the recombination, photons of light may be emitted, resulting in the production of light. Furthermore, in certain cases, the recombination process may also produce radiation. Therefore, all of the above options are possible outcomes when a diode is forward-biased.

The width of the depletion region in a semiconductor is inversely proportional to the doping level. This means that as the doping level increases, the width of the depletion region decreases, and vice versa. The depletion region is a region near the junction of two differently doped regions in a semiconductor device. It is an area depleted of majority charge carriers, creating a barrier for the flow of current. Higher doping levels introduce more charge carriers, reducing the width of the depletion region and allowing for easier current flow. Conversely, lower doping levels result in a wider depletion region and higher resistance to current flow.

A varactor diode is a type of diode that exhibits a voltage-dependent capacitance. This means that the capacitance of the diode can be varied by changing the applied voltage across it. As the voltage increases, the capacitance decreases, and vice versa. This property makes varactor diodes useful in applications such as voltage-controlled oscillators, frequency multipliers, and voltage-controlled filters.

In an intrinsic semiconductor at room temperature, the current is due to the movement of both holes and electrons. In an intrinsic semiconductor, the number of electrons and holes is equal, and they are generated by thermal excitation. The movement of both charge carriers contributes to the overall current flow in the material. Therefore, the correct answer is "Holes and electrons."

In a forward-biased photo diode, the diode current is directly proportional to the incident light intensity. This means that as the incident light intensity increases, more electrons are excited and flow through the diode, resulting in an increase in diode current. Therefore, the correct answer is "Increases".

In an intrinsic semiconductor, the mobility of electrons in the conduction band is greater than the mobility of holes in the valence band. This is because electrons are negatively charged and therefore have a higher mobility compared to positively charged holes. Intrinsic semiconductors have an equal number of electrons and holes, but due to their different mobilities, electrons are more likely to move and contribute to the conduction of electric current.

The measurement of Hall coefficient in a semiconductor provides information on the sign and concentration of charge carriers. The Hall coefficient is a parameter that describes the behavior of charge carriers in a magnetic field. By measuring the Hall coefficient, we can determine whether the charge carriers are positive or negative (sign) and also obtain information about their concentration, which is the number of charge carriers per unit volume.

In a full wave center-taped rectifier, each diode conducts only during the positive half cycle of the input AC signal. This means that the diodes conduct for half of the complete period of the input signal. Since the input signal has a complete period of 3600, each diode conducts for 1800 only.

The bulk resistance of a diode is the sum of the resistance values of the n-material and p-material. This is because the diode is made up of these two materials, and their individual resistances add up to determine the overall resistance of the diode.

A long specimen of p-type semiconductor material is electrically neutral because it has equal numbers of positive charges (holes) and negative charges (electrons). In a p-type semiconductor, impurities are added to the material, creating excess holes which are positively charged. However, the material also has an equal number of negatively charged electrons. As a result, the positive and negative charges balance each other out, making the material electrically neutral.

The probability that an electron in a metal occupies the Fermi-level at any temperature (>0 K) is not 0 or 1. The Fermi level represents the highest energy level that is occupied by electrons at absolute zero temperature. As the temperature increases, some electrons may gain enough energy to occupy higher energy levels above the Fermi level. Therefore, the probability that an electron occupies the Fermi level at any temperature (>0 K) is not definite and can be considered as 0.5.

The measurement of Hall coefficient allows for the determination of the type of conductivity and concentration of charge carriers in a material. The Hall coefficient is a parameter that describes the behavior of charge carriers in a magnetic field. By measuring this coefficient, one can determine whether the material has positive or negative charge carriers, as well as their concentration. Therefore, the correct answer is "Type of conductivity and concentration of charge carriers."

A Zener diode should have both heavily doped p- and n-regions and a narrow depletion region. The heavily doped p- and n-regions allow for a high concentration of charge carriers, which enables the diode to conduct current in both forward and reverse bias. The narrow depletion region is important because it allows for a high electric field to be established across the diode, which is necessary for the Zener effect to occur. The Zener effect is the phenomenon where the diode can maintain a constant voltage drop across it, even with large changes in current.

When the temperature of an extrinsic semiconductor is increased, the intrinsic carrier concentration increases. This increase in intrinsic carrier concentration leads to an increase in both majority and minority carrier densities. The majority carriers are the majority charge carriers in the semiconductor, while the minority carriers are the minority charge carriers. Therefore, when the intrinsic carrier concentration is doubled, both the majority and minority carrier densities double as well.

The electric field in an abrupt p-n junction is a linear function of distance. This means that the electric field strength increases or decreases uniformly as the distance from the junction increases. In an abrupt p-n junction, there is a sharp transition between the p-type and n-type regions, and the electric field is constant within these regions. However, at the junction itself, there is a linear change in the electric field due to the difference in charge carriers and the resulting electric potential.

The correct answer is "np = nipi". In an intrinsic semiconductor, the electron concentration (n) and hole concentration (p) are equal to the intrinsic carrier concentrations (ni and pi, respectively). When doped with a p-type material, the electron concentration increases to n and the hole concentration decreases to p. The product of the electron and hole concentrations (np) remains constant and is equal to the product of the intrinsic carrier concentrations (nipi). This relationship is known as the law of mass action and holds true in doped semiconductors.

A fused junction refers to a p-n junction that is created by recrystallization on a base crystal from a liquid phase of one or more components. In this process, the semiconductor material is melted and then solidified to form the junction. This method allows for precise control over the doping levels and composition of the junction, making it suitable for specific applications in semiconductor devices. The other options, doped junction and alloy junction, do not accurately describe the process of creating a junction through recrystallization from a liquid phase. Therefore, the correct answer is fused junction.

The point where the diode starts conducting is known as the cut-in point. This is the voltage threshold at which the diode allows current to flow in the forward direction. Below this voltage, the diode is in a non-conducting state and does not allow current to pass through. The cut-in point is an important characteristic of a diode as it determines when it starts to function as a rectifier or switch in a circuit.

A semiconductor with an energy gap of 1.1 eV would be opaque to visible light because the energy of visible light photons (approximately 1.65 - 3.1 eV) is higher than the energy gap. This means that visible light photons do not have enough energy to excite electrons across the energy gap, resulting in the semiconductor being unable to transmit or transmit only a small portion of visible light.

The Fermi energy in a p-n junction at thermal equilibrium is invariant with respect to distance. This means that regardless of the position within the junction, the Fermi energy remains constant.

The Hall coefficient of an intrinsic semiconductor is negative under all conditions. The Hall coefficient is a measure of the sign and magnitude of the charge carriers in a material. In an intrinsic semiconductor, the charge carriers are electrons and holes. The negative Hall coefficient indicates that the majority charge carriers in an intrinsic semiconductor are electrons.

Intrinsic silicon is a pure form of silicon with no impurities. In this case, the Hall Effect voltage refers to the voltage generated when an electric current passes through the silicon in the presence of a magnetic field. In intrinsic silicon, the charge carriers are both electrons and holes. When a magnetic field is applied, the electrons and holes will experience a force perpendicular to their motion, resulting in a separation of charge carriers. This separation creates a voltage difference, with the negative charge carriers (electrons) accumulating on one side and the positive charge carriers (holes) accumulating on the other side. Therefore, the Hall Effect voltage in intrinsic silicon is negative.

The diffusion capacitance is not affected by the forward-bias. It remains constant regardless of the biasing condition.

Gold is often diffused into silicon p-n junction devices to modify the electrical properties of the semiconductor material. It does not have a direct relation to the recombination rate or make silicon a direct gap semiconductor. Therefore, the correct answer is "None of the above".