Tunnel junctions for vertically integrated multiple nitrides laser diodes

The tunnel junctions (TJs) in the III-nitrides optoelectronic structures open possibilities for new applications such as vertically integrated multicolor light emitting diodes [1], [2] or laser diodes [3], [4]. In plasma-assisted molecular beam epitaxy (PAMBE) the hydrogen-free growth process is used that allows to obtain p-type conductivity in buried layers without post growth activation. This approach allows to integrate vertically optoelectronic structures with low series resistance TJs. Therefore PAMBE seems to be better suited than metal organic vapor-phase epitaxy (MOVPE) for practical realization of the vertical devices with buried p-type region - especially for laser diodes (LD) containing interband TJs [3]. It was shown by S. Krishnamoorthy et al. that by adding an undoped InGaN quantum well (QW) between heavily doped p-type and n-type GaN layers tunneling probability increases by orders of magnitude [5]. This effect is caused by strong polarization field inside GaN:Mg/InGaN/GaN:Si heterostructure.