Consider an n -type silicon photoconductor that is 1 μm thick, 50 μm wide, and has an applied el

step 1 In this question we have to find the steady state for the current or I for the silicon conductor

Consider an n -type silicon photoconductor that is 1 μm...

Consider an $\mathrm{n}$ -type silicon photoconductor that is $1 \mu \mathrm{m}$ thick, $50 \mu \mathrm{m}$ wide, and has an applied electric field in the longitudinal dimension of $50 \mathrm{~V} / \mathrm{cm}$. If the incident photon flux is $\Phi_{0}=10^{16} \mathrm{~cm}^{-2}-\mathrm{s}^{-1}$ and the absorption coefficient is $\alpha=5 \times 10^{4} \mathrm{~cm}^{-1}$, calculate the steady-state photocurrent if $\mu_{n}=1200 \mathrm{~cm}^{2} / \mathrm{V}-\mathrm{s}$, $\mu_{p}=450 \mathrm{~cm}^{2} / \mathrm{V}-\mathrm{s}$, and $\tau_{p 0}=2 \times 10^{-7} \mathrm{~s}$

Consider an $\mathrm{n}$ -type silicon photoconductor that is $1 \mu \mathrm{m}$ thick, $50 \mu \mathrm{m}$ wide, and has an applied electric field in the longitudinal dimension of $50 \mathrm{~V} / \mathrm{cm}$. If the incident photon flux is $\Phi_{0}=10^{16} \mathrm{~cm}^{-2}-\mathrm{s}^{-1}$ and the absorption coefficient is $\alpha=5 \times 10^{4} \mathrm{~cm}^{-1}$, calculate the steady-state photocurrent if $\mu_{n}=1200 \mathrm{~cm}^{2} / \mathrm{V}-\mathrm{s}$,
$\mu_{p}=450 \mathrm{~cm}^{2} / \mathrm{V}-\mathrm{s}$, and $\tau_{p 0}=2 \times 10^{-7} \mathrm{~s}$

Key Concepts

Photoconductivity

Photoconductivity is the phenomenon in which the electrical conductivity of a material increases when it is illuminated by light. The absorption of photons generates additional electron?hole pairs, thereby enhancing the number of charge carriers available for conduction, which leads to an increase in current through the material.

Carrier Mobility

Carrier mobility refers to the ability of charge carriers, such as electrons or holes, to move through a semiconductor in response to an applied electric field. It is a key parameter that influences how readily carriers can drift and contribute to current flow, with higher mobility resulting in greater drift velocities and increased conductivity.

Optical Absorption Coefficient

The optical absorption coefficient quantifies how efficiently a material absorbs incident photons, which subsequently generate electron–hole pairs. It determines the rate at which the light intensity decays within the material and directly influences the generation rate of charge carriers, affecting the overall photocurrent.

Steady-State Carrier Generation and Recombination

In a photoconductive device, under steady-state conditions, the rate of carrier generation by photon absorption balances the rate of carrier recombination. This equilibrium determines the minority carrier concentration, which is crucial for calculating the net photocurrent derived from the continuous and stabilized production of carriers in the material.

Drift Current

Drift current is the component of the photocurrent produced by the movement of free charge carriers under the influence of an applied electric field. It is calculated by considering the product of the carrier concentration, the carrier mobility, and the strength of the electric field. In photoconductors, the drift current is the main mode of current conduction when carriers created by photon absorption are swept by the electric field through the device.

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