Question

How does temperature affect the band structure and the I-V characteristics of semiconductor devices?

How does changing the carrier lifetime affect semiconductor devices?

For a GaAs PN junction, imagine that the device is to be used as a photo-diode. What width of intrinsic layer would you want to design the device with if the photons only absorb in the depletion/intrinsic regions? Assume: wavelength = 0.75um.

Answer 1

The temperature affect on the band structure of semiconductor devices is that when temperature increases the band gap reduces. Because as thetemperature ncreases energy of electrons increases and thus less energy is required to break the bond. Thus, band gap energy decreases.

The temperature affect on the I-V characteristics of semiconductor devices is that whenteperature increases the current decreases. As T is inversely proportional to current.

If carrier lifetimes changes then current also changes. If carrier lifetime decreases then free carriers(electrons/holes are available for short duration of time so as the number free carriers decreases and hence the current decreases.

For a GaAs PN junction, imagine that the device is to be used as a photo-diode. The width of intrinsic layer would you want to design the device with if the photons only absorb in the depletion/intrinsic regions assuming wavelength = 0.75um. . Sice wavelength is free small(less than 11) for in direct absorbtions threshold is 1.85. And for direct absorbtions is 1.53.