A new structure of three cascade solar cells with graded band-gap layer on the base of GaAs-AlGaAs heterosystem is designed to decrease the thermal losses, arising as a result of absorption of short-wavelength radiation. These solar cells were created by combining liquid-phase epitaxy with gas-phase zinc diffusion technologies. In these structures multilayer cascade elements reduce losses, caused by generation of "hot" carriers and the upper graded band-gap layer improves the conversion of short-wavelength radiation. The cell structure exhibited high short-wavelength sensitivity and the following parameters (under 1-sun conditions): open-circuit voltage (V-oc = 1.03 V); short-circuit current (I-sc = 24.9 mA/cm(2)); fill factor (FF = 0.74) and efficiency (eta = 22.3%). Therefore it can be successfully utilized as power supplies in high-located areas, and as sensors of ultra-violet radiation. (C) 2002 Elsevier Science B.V. All rights reserved.