Self-assembling of In and nitrogen in GaP:(In, N)

• Self-assembling of 4N10In and 1N4In clusters in GaP:(In, N) is described.
• GaP:(In, N) is In(x)Ga(1−x)N(y)P(1−y) substitutional alloy.
• The decrease of the enthalpy and strain energy is the reason of self-assembling.
• The densities of clusters depend on temperature and impurity content.

Highly mismatched GaP:N attracts now considerable interest in fabricating ensembles of single photon sources. Significant reduction of undesirable internal strains around nitrogen atoms can be achieved by additional doping with In due to self-assembling of 4N10In and 1N4In clusters in GaP:(In, N). Double doping transforms GaP into GaP-rich InxGa1−xNyP1−y substitutional alloy of InN, InP, GaN and GaP. Self-assembling of clusters results in the decrease of the sum of the free energies of the constituent compounds and strain energy. The self-assembling conditions are considered from 0 °C to 1000 °C in the dilute and ultra dilute limits for In and nitrogen impurities, respectively. Almost all nitrogen atoms are in 4N10In clusters over the entire temperature range if x = 1 × 10−3, y = 1 × 10−4; x = 1 × 10−4, y = 1 × 10−5 and x = 1 × 10−5, y = 1 × 10−6. Both types of clusters with considerable densities are in GaP-rich InxGa1−xNyP1−y if the ratio between the In and nitrogen contents is 100. If this ratio is ≈1000 then all nitrogen impurities are in 1N4In clusters over the entire temperature range. The fulfilled estimates demonstrate that GaP:(In, N) is a promising candidate to fabricate ensembles of single photon sources due to small strains around nitrogen atoms in 4N10In and 1N4In clusters.