Achieving a high breakdown voltage for GaAsSb-based backward diodes using the carrier depletion effect originating from nanowires

Abstract

The forward breakdown voltage (BV) of GaAsSb-based backward diodes was significantly increased by using nanowire structures. From the structure analysis of the fabricated devices, it was found that the sidewall of the nanowires was completely covered with thin AlOx film and that the top part of the nanowire sidewalls also contains electrode materials. From device simulations, we found that the increased BV originated from the carrier depletion brought by the metal–semiconductor–insulator structure at the top of the nanowires. In addition, this effect strongly depends on the diameters and doping levels of the nanowire. The increased BV achieved with this effect will increase the dynamic range of rectification.

III–V nanowire backward diodes with high sensitivity above 1 MV W−1 for low-power microwave energy harvesting

“…23) We reported the simulation results of the increased FBV in NW-BWDs that were assumed to have a cylindrical NW structure. 22) However, the actual NW BWD exhibited a corn-shaped structure at the top of NWs. Therefore, a tapered NW model was introduced in the simulation herein to elucidate these structural effects of NW BWDs.…”

“…16,17) Sensitivity of the NW BWDs was improved by modifying growth conditions of the NWs and the device structures. 18,19) However, one drawback of BWDs is on their dynamic range, which was limited to below 0 dBm due to their low forward breakdown voltage (FBV) of around 0.4 V. 20) The adoption of extended anode structure in GaAsSb NWs 21,22) shows a significant improvement of the FBV, which signifies that the NW structure contributes not only on improving the sensitivity via the reduction of C j , but also in increasing the dynamic range of microwave power detection.…”