n-InGaN∕p-GaN single heterostructure light emitting diode with p-side down

The effects of negative polarization charge at the n-InGaN∕p-GaN interface on the performance of hydride vapor phase-epitaxy deposited single heterostructure n-InGaN∕p-GaN LEDs with p-side down are investigated. The strong peak emission wavelength blueshift and concomitant superlinear increase in light output as the injection current increases below 25A∕cm2 are characteristic of radiative tunneling. We show that the combination of two-dimensional hole gas formation on the n-InGaN side of the heterointerface and enhancement of the electron barrier to transport across this interface results in only ∼10% efficiency droop up to 500A∕cm2 without implementation of an AlGaN electron-blocking layer or a second heterointerface.