Cryogenic characteristics of GaAs-based near-infrared light emitting diodes

Abstract

High performance infrared light emitting diodes (LEDs) have drawn wide attention because of their significant applications in biomedicine, agriculture, aquaculture, night vision security systems and scientific researches. Due to the rapid development of infrared up-conversion devices, especially in the terahertz region, the studies on the GaAs-based infrared LEDs operating at low temperature (<20 K) are quite needed. In this paper, two representative GaAs-based LEDs (GaAs/AlGaAs double heterostructure LED (DH-LED) and GaAs (InGaAs)/AlGaAs quantum well infrared LED (QW-LED)) are fabricated and characterized with electroluminescence (EL) spectroscopy and electroluminescence efficiency (ELE) at different temperatures. The ELE of the QW-LED is about 70% higher at low temperatures (<150 K) but lower at high temperatures (>150 K) than that of the DH-LED. A developed rate equation method is used to analyze the ELE superiority of the QW-LED. Finally, the surface EL uniformity of the two LEDs is studied by using the charge coupled devices imaging. This study provides a guidance to choose and design LED structures for different operation temperatures.