Ultrabroadband THz/IR upconversion and photovoltaic response in semi-conductor ratchet based upconverter

TL;DR

This paper demonstrates an ultrabroadband THz to IR upconversion device using a semiconductor ratchet photodetector integrated with a GaAs LED, capable of converting blackbody radiation into detectable NIR photons and functioning as a photovoltaic detector.

Contribution

It introduces a novel ultrabroadband upconverter integrating a GaAs/AlGaAs ratchet photodetector with a GaAs LED, covering a wider frequency range than existing devices.

Findings

Achieved ultrabroadband response from 4 to 200 THz.

Successfully upconverted blackbody radiation into detectable NIR photons.

Demonstrated photovoltaic detection in the IR region without bias.

Abstract

An ultrabroadband upconversion device is demonstrated by direct tandem integration of a p-type GaAs/AlxGa1-xAs ratchet photodetector (RP) with a GaAs double heterojunction LED (DH-LED) using the molecular beam epitaxy (MBE). An ultrabroadband photoresponse from terahertz (THz) to near infrared (NIR) region (4-200 THz) was realized that covers a much wider frequency range com-pared with the existing upconversion devices. Broadband IR/THz radiation from 1000 K blackbody is successfully upconverted into NIR photons which can be detected by commercial Si-based device. The normal incidence absorption of the RP simplifies the structure of the RP-LED device and make it more compact compared with the inter-subband transition based upconverters. In addition to the up-conversion function, the proposed upconverter is also tested as photovoltaic detectors in the infrared region (15-200 THz) without an applied bias voltage due to the ratchet effect.