Large-Signal Photomagnetoelectric Effect

Abstract

Photomagnetoelectric measurements made on $p$-type InSb at 80°K are found to disagree with existing theories. The theory is extended to include nonlinear bulk and surface recombination rates which define a "lifetime", ${\tau }_n\left(\Delta n\right)$, and a "surface recombination velocity", $S_n\left(\Delta n\right)$, which are dependent on excess carrier concentration. This extended theory is in good agreement with experiment, and is used to determine ${\tau }_n\left(\Delta n\right)$ and $S_n\left(\Delta n\right)$ as functions of $\Delta n$, to determine the zero-magnetic-field mobility of the minority carrier, and to identify the dominant scattering mechanism. Agreement between theory and experiment is best when ionized impurity type scattering is assumed, yielding a zero-magnetic-field electron mobility of 1.1×${10}^5$ ${\mathrm{cm}}^2$/v-sec. The "lifetime" begins to deviate from its small signal value (1.6×${10}^{-10\mathrm{}}$ sec) when $\Delta n$ exceeds about ${10}^9$ ${\mathrm{cm}}^{-3\mathrm{}}$; it increases by a factor of 20 as $\Delta n$ increases to 5×${10}^{10}$ ${\mathrm{cm}}^{-3\mathrm{}}$. The small-signal "surface recombination velocity" is too small to be determined. It becomes appreciable (the order of 3.5×${10}^4$ cm/sec) when $\Delta n$ is about ${10}^9$ ${\mathrm{cm}}^{-3\mathrm{}}$, increases rapidly to a maximum of 12×${10}^4$ cm/sec when $\Delta n$ is 3.8×${10}^9$ ${\mathrm{cm}}^{-3\mathrm{}}$, and then falls off gradually by a factor of 1.5 when $\Delta n$ reaches 2×${10}^{10}$ ${\mathrm{cm}}^{-3\mathrm{}}$.