Wide-gap, high-conductivity p-type hydrogenated microcrystalline silicon oxide (p-mc-SiO:H) films deposited by very high frequency plasma-enhanced chemical vapor deposition (60 MHz VHF-PECVD) at a low substrate temperature of approximately [200 C] were used as window layers in n-type crystalline silicon (n-c-Si) heterojunction (HJ) solar cells. We investigated the effect of p-mc-SiO:H window layer thickness on HJ solar cells by changing deposition time and silane (SiH 4 ) flow rate. The effects of carbon dioxide flow rate on the p-mc-SiO:H window and i-a-SiO:H buffer layer were also studied. Employing a p-mc-SiO:H/i-a-SiO:H/n-c-Si [Czochralski (CZ), 200 mm, (100)]/ i-a-Si:H/n-a-Si:H configuration, we achieved an efficiency of 17.8% (active area efficiency) with an open-circuit voltage (V oc ) of 665 mV. The solar cells showed a spectral response of about 0.83 at a wavelength of 400 nm, which is higher than that of conventional HJ solar cells with amorphous silicon window layers.

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Using first principles calculation, we systematically investigate the electronic modification of Cu-based chalcopyrite semiconductors induced by lattice deformation and composition alchemy. It is shown that the optical band gap E g is remarkably sensitive to the anion displacement µ, resulting from the opposite shifts of conduction band minimum and valence band maximum. Meanwhile, the dependence of structural parameters of alloyed compounds on alloy composition x is demonstrated for both cation and anion alloying. The d orbitals of group-III cations are found to be of great importance in the calculation. Abnormal changes in the optical band gap E g induced by anion alloying are addressed.

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Polytypes of ordered defect compound CuIn5Se8 were constructed based on chalcopyrite and CuAu-like CuInSe2. First principles calculation was used to perform structural optimization and calculate the total energy. Total energy calculation shows that P4¯ symmetry polytype is slightly stable than P222 symmetry polytype. After structural optimization, P4¯ and P222 symmetry polytypes show small differences in lattice parameters and electronic properties. The calculated band gap of CuIn5Se8 polytypes is 0.30(+0.01)eV higher than that of CuInSe2. The neglect of P222 symmetry polytype is attributed to the imperceptible differences between P4¯ and P222 symmetry polytypes.