Fabrication of heterojunction solar cells by using microcrystalline hydrogenated silicon oxide film as an emitter

Abstract

Wide gap, highly conducting n-type hydrogenated microcrystalline silicon oxide (μc-SiO : H) films were prepared by very high frequency plasma enhanced chemical vapour deposition at a very low substrate temperature (170 °C) as an alternative to amorphous silicon (a-Si : H) for use as an emitter layer of heterojunction solar cells. The optoelectronic properties of n-μc-SiO : H films prepared for the emitter layer are dark conductivity = 0.51 S cm−1 at 20 nm thin film, activation energy = 23 meV and E04 = 2.3 eV. Czochralski-grown 380 µm thick p-type ⟨1 0 0⟩ oriented polished silicon wafers with a resistivity of 1–10 Ω cm were used for the fabrication of heterojunction solar cells. Photovoltaic parameters of the device were found to be Voc = 620 mV, Jsc = 32.1 mA cm−2, FF = 0.77, η = 15.32% (active area efficiency).

Analysis of lateral transport through the inversion layer in amorphous silicon/crystalline silicon heterojunction solar cells

“…18 In practice, the DE vb can be increased by 0.15 eV by increasing the a-Si:H hydrogen content from 12% to 24%. 34 Another possibility is to deposit hydrogenated amorphous silicon suboxide films (a-SiO x :H) with higher bandgaps than a-Si:H. 35,36 In the simulations, the initial DE vb of 0.43 eV was varied by hypothetically changing the front a-Si:H layers' bandgap, while leaving all other parameters the same. Note that widening the bandgap of the emitter and front intrinsic a-Si:H layers would also decrease the UV and visible parasitic absorption in these layers.…”

Preparations of P‐ and N‐doped hydrogenated microcrystalline cubic silicon carbide films by VHF plasma enhanced chemical vapor deposition method for Si thin film solar cells

“…Research and development of wide bandgap materials [1,2] has been advanced for a means to realize silicon (Si) based solar cells with higher energy conversion efficiencies. One of the most promising materials is hydrogenated microcrystalline cubic silicon carbide (μc-3C-SiC:H) films [1,3].…”

Studies on the structural properties of SiO:H films prepared from (SiH4+CO2+He) plasma in RF-PECVD

“…For further improvements in the performance of solar cells, development of SiO:H as a good-quality micro/nano-crystalline material has come up as an important task in view of its high electrical conductivity, high carrier mobility and high doping efficiency, while having high optical transparency. The mc-SiO:H films have uses as an active layer [12], window layer [13] and at the tunnel junction [14] in solar cells. Several attempts have been made by many workers [15,16], including this research group [17,18], on the development of mc-SiO:H films.…”