AlGaAs/GeSn p-i-n diode interfaced with ultrathin Al$_2$O$_3$

TL;DR

This paper reports the fabrication and detailed electrical characterization of an AlGaAs/GeSn p-i-n heterostructure diode with ultrathin Al$_2$O$_3$, demonstrating high uniformity and potential for next-generation GeSn lasers.

Contribution

It introduces a novel heterostructure with ultrathin Al$_2$O$_3$ for enhanced optoelectronic performance and provides comprehensive electrical analysis of high-quality GeSn-based diodes.

Findings

High rectification ratio of 2.95E103 at +/-2 V

Mean ideality factor of 1.47 across devices

Robust electrical confinement and carrier injection

Abstract

This study presents the fabrication and characterizations of an Al$_{0.3}$Ga$_{0.7}$As/Ge$_{0.87}$Sn$_{0.13}$/GeSn p-i-n double heterostructure (DHS) diode following the grafting approach for enhanced optoelectronic applications. By integrating ultra-thin Al$_2$O$_3$ as a quantum tunneling layer and enhancing interfacial double-side passivation, we achieved a heterostructure with a substantial 1.186 eV conduction band barrier between AlGaAs and GeSn, along with a low interfacial density of states. The diode demonstrated impressive electrical characteristics with high uniformity, including a mean ideality factor of 1.47 and a mean rectification ratio of 2.95E103 at +/-2 V across 326 devices, indicating high-quality device fabrication. Comprehensive electrical characterizations, including C-V and I-V profiling, affirm the diode's capability to provide robust electrical confinement and efficient carrier injection. These properties make the Al$_{0.3}$Ga$_{0.7}$As/Ge$_{0.87}$Sn$_{0.13}$/GeSn DHS a promising candidate for next-generation electrically pumped GeSn lasers, potentially operable at higher temperatures. Our results provide a viable pathway for further advancements in various GeSn-based devices.