Ge doping of GaN beyond the Mott transition

Abstract

We present a study of germanium as n-type dopant in wurtzite GaN films grown by plasma-assisted molecular beam epitaxy, reaching carrier concentrations of up to 6.7E20 cm-3 at 300K, well beyond the Mott density. The Ge concentration and free carrier density were found to scale linearly with the Ge flux in the studied range. All the GaN:Ge layers present smooth surface morphology with atomic terraces, without trace of pits or cracks, and the mosaicity of the samples has no noticeable dependence on the Ge concentration. The variation of the GaN:Ge band gap with the carrier concentration is consistent with theoretical calculations of the band gap renormalization due to electron-electron and electron-ion interaction, and Burstein-Moss effect.

References in corpus (3)

• Gallium adsorption on (0001) GaN surfaces
• Screening of the quantum-confined Stark effect in AlN/GaN nanowire superlattices by Germanium doping
• Long-lived excitons in GaN/AlN nanowire heterostructures

Cited by in corpus (5)

• Electrical and Optical Properties of Heavily Ge-Doped AlGaN
• Effect of doping on the intersubband absorption in Si- and Ge-doped GaN/AlN heterostructures
• Solubility limit of Ge Dopants in AlGaN: a Chemical and Microstructural Investigation down to the Nanoscale
• Effect of Ge-doping on the short-wave, mid- and far-infrared intersubband transitions in GaN/AlGaN heterostructures
• Limitation of simple np-n tunnel junction based LEDs grown by MOVPE