Realization of radial p-n junction silicon nanowire solar cell based on low-temperature and shallow phosphorus doping

Abstract

A radial p-n junction solar cell based on vertically free-standing silicon nanowire (SiNW) array is realized using a novel low-temperature and shallow phosphorus doping technique. The SiNW arrays with excellent light trapping property were fabricated by metal-assisted chemical etching technique. The shallow phosphorus doping process was carried out in a hot wire chemical vapor disposition chamber with a low substrate temperature of 250°C and H2-diluted PH3 as the doping gas. Auger electron spectroscopy and Hall effect measurements prove the formation of a shallow p-n junction with P atom surface concentration of above 1020 cm−3 and a junction depth of less than 10 nm. A short circuit current density of 37.13 mA/cm2 is achieved for the radial p-n junction SiNW solar cell, which is enhanced by 7.75% compared with the axial p-n junction SiNW solar cell. The quantum efficiency spectra show that radial transport based on the shallow phosphorus doping of SiNW array improves the carrier collection property and then enhances the blue wavelength region response. The novel shallow doping technique provides great potential in the fabrication of high-efficiency SiNW solar cells.

Passivation of high aspect ratio silicon nanowires by using catalytic chemical vapor deposition for radial heterojunction solar cell application

“…A conventional planar hetero-junction (P-HET) solar cell was prepared on polished wafer under the same procedure as RJ-HET solar cell. A RJ-HOMO solar cell was prepared on SiNWs by low temperature catalytic shallow diffusion technology 6 carried out in the Cat-CVD chamber under a substrate temperature of 250 C. H 2 -diluted PH 3 (0.5%) was used as the doping gas. Aer a 25 min doping, a junction depth of about 10 nm can be formed and a radial-homojunction structure can be obtained on the SiNWs.…”

“…In 2007, Tian et al 3 rst reported a coaxial single SiNW based radial p-i-n solar cell prepared by vapor-liquid-solid technique which obtained a conversion efficiency of 3.4%. Aer that, with application of lithography and high temperature diffusion 4,5 or combination of metal-assisted chemical etching (MACE) and low temperature catalytic shallow doping, 6 radial p-n junction concept has been implemented on SiNWs arrays and reported efficiency increased up to >13%. However, the reported performances can still hardly meet people's expectation.…”

Fabrication and Photovoltaic Effect of CdS/Silicon Nanopillars Heterojunction Solar Cell

“…One of the good candidates is heterojunction solar cells formed simply by depositing transparent semiconductor films on silicon substrates. The heterojunction solar cells have a number of potential advantages such as an excellent blue response, simple processing steps, and low processing temperatures …”

Fabrication of silicon solar cell with >18% efficiency using spin-on-film processing for phosphorus diffusion and SiO2/graded index TiO2 anti-reflective coating

“…The formation of shallow p-n junctions in silicon (Si) is an important step in the fabrication of photovoltaic devices [1][2][3][4][5]. Using ion implantation, excimer laser annealing, and thermal diffusion of dopants into the Si wafer forming a p-n junction are expensive approaches [2,[6][7][8][9][10][11].…”