Abstract

Subject of study. The effect of temperature on the optical and noise characteristics of ultraviolet InGaN/GaN industrial light-emitting diodes in a wide temperature range of −196^∘C−84^∘C is studied. Aim of study. The aim is to check the operability of ultraviolet indicator light-emitting diodes under temperature conditions other than room temperature, determine the relative changes in the main optical characteristics and reliability characteristics, and discuss the possible physical mechanisms responsible for the observed changes. Method. The measuring chamber, designed for temperature measurements from −196^∘C to 100°C, uses a platinum temperature sensor with a polynomial approximation (from −200^∘C to +100^∘C). Noise characteristics were estimated using an STC-H246 tuning-fork analog-to-digital converter with an intrinsic noise level of 1 µV. Main results. It has been found that heating improves the optical characteristics of ultraviolet InGaN/GaN light-emitting diodes. The density of low-frequency noise does not increase significantly and increases up to two times (40°C, 84°C) only at nominal currents (20 mA). This result contradicts the traditional understanding of the characteristics of heated semiconductor optoelectronic devices. We provide explanations for this by considering the features of carrier transport involving carrier tunneling through defects and "tails" of the density of states in barriers to quantum wells, which have not been used by other authors. Upon cooling (−196^∘C), the density of low-frequency current noise increases and the external quantum efficiency at the nominal current decreases by a factor of 1.6, which is also in contrast to the conventional understanding. Practical significance. Considering applications, the results of this study are of practical interest for the development and improvement of ultraviolet light-emitting devices based on structures with InGaN/GaN quantum wells. They can help estimate their reliability and service life and can be useful for electronic equipment designers who use these elements in special climatic conditions, as they allow for a broader range of operating currents and temperatures.

© 2024 Optica Publishing Group