Fast and efficient Sb-based type-II phototransistors integrated on silicon
Year: 2025
Type: article
Abstract: Increasing the energy efficiency and reducing the footprint of on-chip photodetectors enable dense optical interconnects for emerging computational and sensing applications. While heterojunction phototransistors (HPTs) exhibit high energy efficiency and negligible excess noise factor, their gain-bandwidth product (GBP) has been inferior to that of avalanche photodiodes at low optical powers. Here, we demonstrate that utilizing type-II energy band alignment in an Sb-based HPT results in six times smaller junction capacitance per unit area and a significantly higher GBP at low optical powers. These type-II HPTs were scaled down to 2 μm in diameter and fully integrated with photonic waveguides on silicon. Thanks to their extremely low dark current and high internal gain, these devices exhibit a GBP similar to the best avalanche devices (∼270 GHz) but with one order of magnitude better energy efficiency. Their energy consumption is about 5 fJ/bit at 3.2 Gbps, with an error rate below 10−9 at −25 dBm optical power at 1550 nm. These features suggest new opportunities for creating highly efficient and compact optical receivers based on phototransistors with type-II band alignment.
Source: APL Photonics
DOI: 10.1063/5.0233887
Language: English
Topic: Photonic and Optical Devices
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,750
Awards: G1313983767, G154696372, G1664757510, G2287611682, G262962599, G3075337988, G3273898808, G3578929740, G4404904460, MRSEC: Center for Multifunctional Materials, G498139845, G5405581032, NNCI: Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource, G585908603, G6848031779, G6918803902, G716412294, G86560745, G9000321923, G969889393
OpenAlex ID: W4408109850