Bidirectional LED as an AC-driven visible-light source

Abstract

Abstract The GaN-based light emitting diodes (LEDs) brought a revolution in the lighting market by becoming the most energy-efficient light sources. However, the power grid, i.e. electricity delivery system, is built based on alternating current (AC), which raises problems for directly driving LEDs that require direct current (DC) to operate effectively. In this paper, we demonstrate a proof of concept device that addresses this fundamental issue – a GaN-based bidirectional light emitting diode (BD LED). The BD LED structure is symmetrical with respect to the active region, which, depending on the negative or positive bias, allows for the injection of either electrons or holes from each side. It is composed of two tunnel junctions that surround the active region. The optical and electrical properties of such BD LEDs under DC and AC conditions are investigated. We find that the light is emitted in both directions of supplied current, contrary to the standard LEDs, hence BD LEDs can be considered as a semiconductor light source powered directly with AC. In addition, we show that BD LEDs can be stacked vertically to multiply the optical power achieved from a single device.