Semiconductor Physics And Electronic Devices

A photodiode is a semiconductor device that can detect light influence. It operates by converting light energy into electrical current. When light falls on the photodiode, it generates electron-hole pairs, which create a current flow. This current can then be measured and used to detect the presence or intensity of light. Unlike other semiconductor devices listed, such as a resistor, capacitor, or inductor, a photodiode specifically designed for light detection and is commonly used in various applications like optical communication, light sensing, and imaging.

Metals have higher conductivity compared to dielectrics and semiconductors. This is because metals have a large number of free electrons that are able to move easily through the material, allowing for the flow of electric current. In contrast, dielectrics have very few free electrons and semiconductors have a moderate number of free electrons, resulting in lower conductivity.

A transistor is a semiconductor device that can amplify electrical signals. It is commonly used in electronic circuits to amplify weak signals or switch electronic signals on and off. Unlike other devices listed, such as resistors, capacitors, inductors, diodes, and photodiodes, a transistor has the ability to provide significant signal amplification, making it the correct answer for this question.

A field effect transistor (FET) typically has three pins: one source, one gate, and one drain. The source is where the current enters, the gate controls the flow of current, and the drain is where the current exits. Therefore, the correct answer is "1 source, 1 gate, and 1 drain."

The operating temperature range of ICs, computers, and other semiconductor devices is conditioned by the used semiconductor material's band gap. The band gap refers to the energy difference between the valence band and the conduction band in a semiconductor. A larger band gap allows the material to withstand higher temperatures without the electrons in the valence band gaining enough energy to jump to the conduction band, which could lead to device failure. Therefore, a larger band gap corresponds to a wider temperature range in which the semiconductor device can operate reliably.

In saturation mode, both the emitter and collector junctions of a bipolar transistor are forward-biased. This means that the emitter junction is forward-biased, allowing electrons to flow from the emitter to the base, and the collector junction is also forward-biased, allowing current to flow from the collector to the base. This configuration allows the transistor to operate in its maximum current-carrying capacity.

Yes, the gate of a field effect transistor is isolated from its channel. This means that there is no direct electrical connection between the gate and the channel. The gate controls the conductivity of the channel by creating an electric field that attracts or repels charge carriers, thus modulating the channel current. This isolation is achieved by using a thin insulating layer, typically made of silicon dioxide, between the gate and the channel.

The correct answer is "Interval increases when increasing density". This means that as the density of lightly degenerated n-region impurities in a tunnel diode increases, the range of negative differential resistance current also increases. This implies that the tunnel diode becomes more sensitive to changes in current as the impurity density increases.

Field effect transistors (FETs) have a small noise coefficient compared to bipolar transistors. This means that FETs produce less noise in their operation, making them more suitable for applications where low noise is desired, such as in audio amplifiers or sensitive electronic circuits. The noise coefficient is a measure of the amount of unwanted electrical signals or interference generated by a device, and a smaller coefficient indicates a lower level of noise. Therefore, FETs are preferred over bipolar transistors in situations where noise reduction is important.

The electrical resistance of an ohmic contact does not depend on the current direction in case of any current value flowing through it. This means that the resistance remains the same regardless of the direction of current flow. This is a characteristic of ohmic contacts, which have a linear relationship between current and voltage. In other words, the resistance remains constant regardless of the direction or magnitude of the current.

The given statement is incorrect because the quality factor of an integrated capacitor does not depend on the resistance of a resistor sequentially connected with the transistor. The quality factor is solely determined by the operating frequency and the capacitance of the capacitor.

The given statement is wrong because ultraviolet beams are not used in electron beam lithography. In this method, electron beams are used as a source of radiation, not ultraviolet beams.

The charge carriers' concentration in the n-type Ge sample is 1.16*10^21 m-3, which means there are 1.16*10^21 charge carriers per cubic meter. The mobility of the charge carriers is 0.36 m2/V*s, indicating how easily they can move in response to an electric field.

The response time of a photodiode is generally conditioned by the diffusion time of equilibrium carriers in the base, their transit time through the layer of p-n junction, and the RC constant of the diode structure. These three conditions affect the time it takes for the photodiode to respond to changes in incident light and generate an output signal.

The statement "In unipolar transistors current control is carried out by the vertical electrical field" is incorrect. In unipolar transistors, current control is not carried out by the vertical electrical field. Unipolar transistors, also known as field-effect transistors (FETs), control current through the modulation of a charge carrier concentration in a semiconductor channel. This modulation is achieved by applying a voltage to the gate terminal, which creates an electric field that controls the flow of majority carriers (either electrons or holes) in the channel. The vertical electrical field does not play a role in current control in unipolar transistors.

Increasing the lifetime of electrons does not directly affect their diffusion length. The diffusion length is determined by other factors such as the material properties and the presence of impurities or defects. Therefore, increasing the lifetime of electrons will not have any effect on their diffusion length.

The high frequency property of a Schottky diode is conditioned by excluding the accumulation of minority carriers in the diode. This means that the diode is designed in a way that prevents the buildup of minority carriers, which allows for faster switching speeds and better high-frequency performance. The other options, such as moving majority carriers through the diode, the value of the Schottky barrier, and the impurity density in a semiconductor, are not directly related to the high frequency property of the Schottky diode.

Varicaps are also known as variable capacitance diodes. In varicaps, the capacitance value changes with the applied voltage. As the voltage increases, the barrier capacitance decreases, not increases. Therefore, the statement "In varicaps with increase of voltage barrier capacitance increases" is incorrect.

The generation frequency in a Gunn diode depends on the sample length. The sample length determines the resonant frequency of the device, which is the frequency at which the diode oscillates. A longer sample length will result in a lower resonant frequency, while a shorter sample length will result in a higher resonant frequency. Therefore, the sample length plays a crucial role in determining the generation frequency of a Gunn diode.

The cutoff voltage of a MOS transistor can change by two ways: by the opposite voltage of the substrate-channel junction when the substrate resistance is equal or smaller than the channel resistance, and by the voltage applied to the gate.