Germanium oxide passivation for Ge absorber
Journal
IEEE Photovoltaic Specialists Conference
Pages
000459-000461
Date Issued
2011
Author(s)
Abstract
In photovoltaic industry, Ge material also plays an important role for III-V solar cells since Ge with smaller band-gap than Si is used as the bottom junction to absorb the infrared (IR) light, so the Ge layer passivation becomes more important. GeO 2 is a suitable material to passivate the surface due to the decrease of the interface defect density (D it) and the introduction of positive fixed charge. The excess carriers in the bulk Ge are generated without nonradiative recombination since the front surface recombination velocity (SRV) is reduced by GeO 2 layer passivation. The metal oxide semiconductor (MOS) capacitors show almost no frequency dispersion from 1 K to 1 MHz at room temperature for oxidation time of 1 and 5 hour. The minimum value of D it with 5 hour oxidation treatment is obtained around 1.8×10 11 cm -2eV -1 by high-low frequency method. Furthermore, adding Al 2O 3 capping layer on GeO 2 layer is used to avoid moisture in the air. © 2011 IEEE.
Other Subjects
Capping layer; Excess carriers; Fixed Charges; Frequency dispersion; Front surfaces; High-low frequency; III-V solar cells; Interface defects; Metal-oxide- semiconductorcapacitors; Minimum value; Non-radiative recombinations; Oxidation time; Oxidation treatments; Photovoltaic industry; Room temperature; Dispersions; Germanium oxides; Interfaces (materials); MOS capacitors; Passivation; Photovoltaic effects; Silicon solar cells; Germanium
Type
conference paper