An In-defect complex as a possible explanation for high luminous efficacy of InGaN and AlInN based devices

Abstract

The role of indium in GaN and AlN films is investigated with the method of the perturbed angular correlation (PAC). Using the PAC probe 111 In in addition to indium on substitutional cation sites a large fraction of probes is found in a distinctly different microscopic environment which was attributed to the formation of an indium nitrogen-vacancy (V N ) complex. The influence of an electron capture induced after ef fect is ruled out by additional measurements with the PAC probes 111m Cd and 117 Cd and using GaN with different dopants. It is shown that the V N is not bound to substitutional Cd impurities suggesting that the In-V N complex formation is a particularity of In in GaN and AlN. Finally, a preliminary model is presented to explain the temperature behavior of the electric field gradient, observed in the In-V N complex measured with 111 In.This work reports on PAC measurements in InGaN and AlInN using Cd-111m and Cd-117 probes. The results show that a signal previously observed using In-111 arises from an In-nitrogen-vacancy complex and is not influenced by an electronic aftereffect. The background, experimental method, and results are all described well. In short, the work reported is of high quality, and I recommend the manuscript for publication without modification.

Cd ion implantation in AlN

“…XRD is very sensitive to low damage levels and suggests a full recovery of the low fluence sample already at moderate annealing temperatures. This result is in agreement with PAC measurements which reveal a good recovery of the crystal and the incorporation of In and Cd probes on distinct lattice sites for fluences below 10 13 at/cm 2 [22,28]. These results are in agreement with the assumption that mainly point defects are formed at these low fluences.…”

Green laser diodes with constant temperature growth of InGaN/GaN multiple quantum well active region

“…A singleexponential fitting from the steady-state intensity to the 1/e of the steady-state intensity is chosen to extract the nonradiative recombination lifetime at equilibrium. In agreement with the PL intensity behavior, the nonradiative recombination lifetime increases from 31 ns to 45 ns when the V/III ratio is increased, indicating a decreasing concentration of nonradiative recombination centers, which we attribute to decreased trench defects [7][8][9][10][11][12][13][14][15][16] and nitrogen vacancy (V N ) or its complex, [22][23][24][25] as discussed in more detail in the next paragraph.…”

Defects and Reliability of GaN‐Based LEDs: Review and Perspectives

“…N‐vacancies (V N ) may originate potential NRRCs [ 19 ] when they form complexes with indium atoms [ 52,53 ] or with gallium vacancies, resulting in this latter case in V N –V Ga divacancies. [ 54 ] However, their low activation energy, 90 meV < E a < 270 meV, and small capture cross section, 2.5 × 10 −20 cm 2 < σ < 4.4 × 10 −14 cm 2 , does not allow to mark isolated V N as the most worrying species in terms of nonradiative SRH recombination.…”

“…Regarding the latter group, we can see that trap signatures ascribed to nitrogen interstitials, extended defects, and C-related defects appear to offer the worse combination of activation energies and apparent cross sections. N-vacancies (V N ) may originate potential NRRCs [19] when they form complexes with indium atoms [52,53] or with gallium vacancies, resulting in this latter case in V N -V Ga divacancies. [54] However, their low activation energy, 90 meV < E a < 270 meV, and small capture cross section, 2.5 Â 10 À20 cm 2 < σ < 4.4 Â 10 À14 cm 2 , does not allow to mark isolated V N as the most worrying species in terms of nonradiative SRH recombination.…”