A novel Field Effect Photodiode to control the output photocurrent and fast optical switching

Abstract

This paper presents a novel device named Field Effect Photodiode (FEPD) to overcome the inherent drawbacks of PIN Photodiode (PIN-PD) and having an accurate control of the output photocurrent either applying the regular PIN-PD as a fast optical switch that provides a desire ION/IOFF ratio for optical applications in the nanoscale regime. The proposed device combines a Metal Semiconductor Field Effect Transistor (MESFET) and a regular PIN-PD device that can convert the incident light with photon energy greater than the semiconductor's bandgap to the regulated photocurrent by changing the gates bias which mounted over the absorption region. Our work include additional models such as bandgap narrowing, Shockley-Read-Hall (SRH), Auger (AUGER), the dependence of the carrier mobility on the doping concentration, Lombardi mobility model (CVT), Fermi statistic dependence (FERMIDIRAC), and Lateral electric field-dependent mobility. To extract and illustrate the electrical and optical results of both the regular PIN-PD and the proposed FEPD in this work, we have used TCAD tools as a semiconductor simulator.

Modified Uni-Traveling-Carrier Photodetector with Its Optimized Cliff Layer

“…However, excessively high doping concentrations will deteriorate PD's breakdown characteristics. Thus, researchers mainly utilized the electron's transient overshoot characteristic to increase electron's equivalent drift velocity in depleted layer and improve the saturation current density [11,[22][23][24]. The near-ballistic UTC-PD achieves a saturation output current of 30 mA by adjusting the electric field intensity to make electrons in the collection layer transport at an overshoot velocity [22].…”

“…It is demonstrated that the electron drift velocity increases from 9 × 10 6 cm/s to 4 × 10 7 cm/s when the photocurrent increases from 1 mA to 20 mA [23]. In addition to the influence of photocurrent on carriers' transport and velocity, changes in bias voltage can also adjust the distribution and transport of carriers inside the device, so the current output can be precisely controlled [24]. However, space-charge screening (SCS) is also a major issue, limiting the saturation current of a PD.…”