The competition for cheap solar energy has led the industry to focus on thinning ultrathin gaas solar cells to reduce manufacturing costs and material usage, and solve the problem of material scarcity (TE, in, GA). Thin film ultrathin gaas solar cells can effectively absorb light within a few microns by using direct band gap semiconductors. A record single junction solar cell with 1-2 micron thick GaAs absorber and short-circuit current close to MA / cm2 has been obtained.A thin film gallium arsenide (GaAs) solar cell is used to replace the silicon solar cell and gallium arsenide crystal base solar cell widely used at present, so as to solve the defects of low photoelectric conversion efficiency, poor resistance to cosmic environmental conditions, heavy weight and high cost price of gallium arsenide crystal base ultrathin gaas solar cells, With the advantages of high mechanical strength, high photoelectric conversion efficiency and good resistance to cosmic environmental conditions, a layer of GaAs thin film is formed on silicon crystal by metal organic chemical vapor deposition (MOCVD) to form thin-film GaAs solar cells.
Ultrathin GaAs solar cells with silver back mirror and absorber thickness of only t = 120 nm and T = 220 nm. Silver back mirror is combined with local ohmic contact. If not has anti reflective coating, because the resonance results in strong enhancement of one-way absorption (up to 4), and the external quantum efficiency reaches 0.8 at the resonance wavelength. The analytical model is employed to work out the resonance wavelength and absorption maximum. Due to the absorption enhancement caused, the short is improved by 27%. By applying a further antireflective coating, the short-circuit current reached 16.3 MA / cm2 for t = 120 nm and 20.7 MA / cm2 for t = 220 nm, like an efficiency of 8.7% and 12.9%, respectively.