Characteristics of bulk InGaAsN and InGaAsSbN material grown by metal organic vapor phase epitaxy (MOVPE) for solar cell application

Abstract

ABSTRACT Bulk, lattice-matched InGaAsSbN material has been grow n by metal organic vapor phase epitaxy (MOVPE) for applications in concentrated multi-junction solar cells. By optimizing the growth conditions for high Sb and As partial pressures, we achieved backgroun d hole concentrations as low as 2 x 10 18 cm -3 . After thermal annealing, the background hole concentration increased from 2x10 18 to 2 x 10 19 cm -3 , although PL intensity increased by a factor of 7. We recently grew single junction (1eV) sola r cells incorporating dilute-nitride materials and devices were fabricated and characterized for solar cell application. Performance characteristics of these cells without anti-reflection coating included the efficiency of 4.25% under the AM1.5 (air mass) direct illumination, V oc of 0.7 V, and a spectral response extended to longer wavelength compared with GaAs cells. 1. INTRODUCTION Several approaches have been pursued to achieve a 1 eV energy band gap material which can be easily integrated into multi-junction solar cells on GaAs substrates. These methods include lattice-matched dilute-nitride materials such as InGaAsN(Sb) [1,3,4,6,7,9,10] and lattice-mismatched In