Fully Porous GaN p–n Junction Diodes Fabricated by Chemical Vapor Deposition

Abstract

Introduction

(Invited) Fully Porous GaN p-n Junctions Fabricated by Chemical Vapor Deposition: A Green Technology towards More Efficient LEDs

“…This turn-on voltage is even lower in the fully porous p-n junctions, lying in the range (E g /4q) -(E g /6q), resembling more the response observed in InN, GaN and other p-n junctions nanowires arrays (51,52). Microscopic characterization confirmed well-defined interfaces between the porous and the non-porous GaN (50), indicating that no significant tunneling barriers exist either at the GaN-GaN interface or on the surface of the GaN/Ohmic contacts. Thus, the barrier potentials are a function of the donor and acceptor densities.…”

“…Thus, n-type (48) or p-type (43) porous GaN epitaxial layers were deposited on non-porous GaN substrates with complementary electrical conductivity to produce partially porous GaN diodes. To produce fully porous GaN diodes by CVD, a two step synthesis process was used in which first a n-type or p-type porous GaN epitaxial layer was produced, and then in the second step a new porous GaN epitaxial layer with complementary electrical conductivity was overgrown on the previous porous layer (50), as can be seen in the scheme shown in Figure 7 (a).…”

Location and Visualization of Working p-n and/or n-p Junctions by XPS

“…Recent SEM characterizations of GaN nanorods have extended conventional mapping by adding in-situ electrical biasing thus enabling the direct imaging of the p-n junction under operational conditions and yielding critical information on its depletion width89. Other techniques like cathode-luminescence in a scanning transmission microscope (CL-STEM)10 and conductive atomic force microscopy (AFM) have also been utilized for the characterization of the p-n junction in GaN nanorods11 and porous GaN based LEDs12. The properties of p-n junctions in photodiodes and photovoltaics have also been extensively investigated using a combination of electrical and optical analyses tools13141516171819.…”

Enhanced excitonic emission efficiency in porous GaN

“…Regarding wide band gap semiconductors, very impressive results were recently published concerning white light emission using porous silicon carbide, a chemically inert semiconductor 7 . Applications of porous gallium nitride and related heterostructures already appear in various areas, among which are the high sensitivity hydrogen gas sensors 8 , water splitting 9 , energy storage 10,11 , development of a new substrate transfer technology 12 , fabrication of light-emitting devices 13,14 and microcavities 15 .…”