GaSb photovoltaic cells for laser power conversion

This study is aimed at the development of laser-radiation converters (LPC) for the wavelength of 1550 nm, which can operate efficiently upon the increase of irradiation power. The photovoltaic structures are produced by Zn diffusion from the gas phase into n-GaSb bulk wafers or base layers grown by liquid phase epitaxy. The output parameters of developed converters with the total size of 4 mm2 are studied at uniform (flash lamp) and partly non-uniform (laser beam) illumination distributions on the LPC surface. Under the Xe-lamp the cells have demonstrated the monochromatic efficiency of 28.4% at laser power ∼1.5 W. In addition, the growth of epitaxial base layer and the reduction of contact-grid shadow from 20% to 10% allow one to enhance the LPC estimated efficiency up to ∼40%. Under illumination by the continuous laser (λ=1550 nm) through the optical fiber with the radiation intensity of 1.4 W the maximum output power of LPCs is 365 mW, which corresponds to the PV power density of ∼20 W/cm2.