Electric field controlled charge transport in an InGaAs/InP photodetector

This study reports the room temperature testing of an InGaAs/InP photodetector, biased under linear sweep and/or parametric bias voltage for both modulated, and unmodulated 1550 nm wavelength illuminations. Charge transport of the photo-generated carriers is probed under absorber’s electric field manipulations via parametric control of applied bias, readout element, and light intensity. The device exhibits three different illumination intensity dependent current signatures. Speed of the employed device is enhanced under relatively stronger electric fields ensuring higher drift, and reduced transit times. A three order reduction in the gain setting of the readout element results in \(\sim 235\) $\sim 235$ times large peak-current under 20 times smaller pulsed illumination of \(0.2 \,\mu \text{W}\) $0.2\mu \text{W}$ . This electric field enhancement decreases rise, and fall times under pulsed illumination from \(225 \,\text{ns}\) $225\text{ns}$ to \(115 \,\text{ns}\) $115\text{ns}$ , and \(1.553\, \mu \text{s}\) $1.553\mu \text{s}$ to \(1.143 \,\mu \text{s}\) $1.143\mu \text{s}$ , respectively. But, the large photodetection plausibility, and reduced transit times ensuring relatively fast speed comes at the expense of ~ 5 order high noise activity in the device. It is also inferred that, overall noise spectrum of the device is not decided by simple generational processes in the absorber, but through the actual proportion of photo-generated carriers taking part in the real charge transport.