This study presents near-optimal single-photon sources in solid-state systems, demonstrating devices that generate highly indistinguishable and pure single photons with high brightness. The sources are based on quantum dots (QDs) embedded in electrically controlled cavity structures. By applying an electrical bias, charge noise effects are fully canceled, leading to a high indistinguishability of 0.9956 ± 0.0045 and a second-order correlation function g²(0) of 0.0028 ± 0.0012. The photon extraction efficiency is 65%, and the brightness is 0.154 ± 0.015, making this source 20 times brighter than any source of equal quality. These sources enable high-purity, highly-indistinguishable single photons with high brightness, essential for quantum communication, quantum simulation, and quantum computing. The devices are fabricated using a planar λ cavity with an InGaAs QD layer and GaAs/Al₀.₉Ga₀.₁As distributed-Bragg-reflectors. The cavity design allows for efficient photon extraction and precise control of the QD-cavity coupling. The devices are characterized under non-resonant and resonant excitation, showing high purity, brightness, and indistinguishability. Under resonant excitation, the indistinguishability reaches 0.9956 ± 0.0045, with a g²(0) of 0.0028 ± 0.0012. The brightness is 0.16 ± 0.02, and the photon extraction efficiency is 0.63. The study compares these solid-state sources with other QD and SPDC sources, showing that the solid-state sources outperform SPDC sources in terms of brightness and indistinguishability. The results demonstrate that the solid-state sources can achieve near-unity indistinguishability and high brightness, making them suitable for quantum technologies requiring high-purity, highly-indistinguishable single photons. The devices are fabricated using a fully deterministic technology, allowing for reproducible and scalable device fabrication. The results highlight the potential of these sources for applications such as Boson sampling and fault-tolerant linear optical quantum computation.This study presents near-optimal single-photon sources in solid-state systems, demonstrating devices that generate highly indistinguishable and pure single photons with high brightness. The sources are based on quantum dots (QDs) embedded in electrically controlled cavity structures. By applying an electrical bias, charge noise effects are fully canceled, leading to a high indistinguishability of 0.9956 ± 0.0045 and a second-order correlation function g²(0) of 0.0028 ± 0.0012. The photon extraction efficiency is 65%, and the brightness is 0.154 ± 0.015, making this source 20 times brighter than any source of equal quality. These sources enable high-purity, highly-indistinguishable single photons with high brightness, essential for quantum communication, quantum simulation, and quantum computing. The devices are fabricated using a planar λ cavity with an InGaAs QD layer and GaAs/Al₀.₉Ga₀.₁As distributed-Bragg-reflectors. The cavity design allows for efficient photon extraction and precise control of the QD-cavity coupling. The devices are characterized under non-resonant and resonant excitation, showing high purity, brightness, and indistinguishability. Under resonant excitation, the indistinguishability reaches 0.9956 ± 0.0045, with a g²(0) of 0.0028 ± 0.0012. The brightness is 0.16 ± 0.02, and the photon extraction efficiency is 0.63. The study compares these solid-state sources with other QD and SPDC sources, showing that the solid-state sources outperform SPDC sources in terms of brightness and indistinguishability. The results demonstrate that the solid-state sources can achieve near-unity indistinguishability and high brightness, making them suitable for quantum technologies requiring high-purity, highly-indistinguishable single photons. The devices are fabricated using a fully deterministic technology, allowing for reproducible and scalable device fabrication. The results highlight the potential of these sources for applications such as Boson sampling and fault-tolerant linear optical quantum computation.