Tunnel junction devices with monolithic optically pumped and electrically injected InGaN quantum wells for polarized white light emission

Abstract

We demonstrate polarized white light emission from a semipolar device in which a tunnel junction is used to monolithically integrate a blue electrically injected light-emitting diode (LED) and yellow-emitting InGaN quantum wells (QWs) that are optically pumped by the LED emission. Polarized white light has important applications, for example, in backlighting liquid crystal displays. The use of a tunnel junction allows the optically pumped QWs for long wavelength emission to be grown after the blue LED, which protects the high indium content InGaN layers from high temperature growth steps and thermal damage. The tunnel junction allows n-GaN above the tunnel junction to be used for current spreading across the LED area, and our molecular beam epitaxy (MBE) tunnel junction growth technique enables buried p-GaN. Optically pumping—rather than electrically injecting—offers several advantages for realizing long wavelength emission from InGaN QWs, and growth on (2021) enables optically polarized emission.