Room temperature negative differential resistance in terahertz quantum cascade laser structures

Asaf Albo, Qing Hu, John L. Reno

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

The mechanisms that limit the temperature performance of GaAs/Al0.15GaAs-based terahertz quantum cascade lasers (THz-QCLs) have been identified as thermally activated LO-phonon scattering and leakage of charge carriers into the continuum. Consequently, the combination of highly diagonal optical transition and higher barriers should significantly reduce the adverse effects of both mechanisms and lead to improved temperature performance. Here, we study the temperature performance of highly diagonal THz-QCLs with high barriers. Our analysis uncovers an additional leakage channel which is the thermal excitation of carriers into bounded higher energy levels, rather than the escape into the continuum. Based on this understanding, we have designed a structure with an increased intersubband spacing between the upper lasing level and excited states in a highly diagonal THz-QCL, which exhibits negative differential resistance even at room temperature. This result is a strong evidence for the effective suppression of the aforementioned leakage channel.

Original languageEnglish
Article number081102
JournalApplied Physics Letters
Volume109
Issue number8
DOIs
StatePublished - 22 Aug 2016
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2016 Author(s).

Fingerprint

Dive into the research topics of 'Room temperature negative differential resistance in terahertz quantum cascade laser structures'. Together they form a unique fingerprint.

Cite this