ABSTRACT

Different strain-balanced InGaAs/InGaAs MQWs were grown on InP for thennophotovoltaic applications. Increasing the elastic strain in the structures results in wavy growth onset which occurs after a critical value of the elastic energy density is achieved. A decrease of the growth temperature leads the critical energy to shift to higher values. The strain-balanced (SB) approach for the growth of strained multi-quantum wells (MQWs) has attracted considerable interest as active components of devices which require an elevated number of quantum wells like optical modulators, laser structures, photodetectors and photovoltaic cells. The InGaAs/InGaAs SB MQWs were grown on InP substrates by metal-organic vapour phase epitaxy. The SB cells were designed to absorb at around 2~m. A compressive well misfit of about 1.5% corresponding to a 0.75 Indium molar fraction is needed for this long wavelength performance. The wavy growth mode in strain balanced InGaAs/InGaAsllnP MQWs is found to start after a critical value of the elastic energy density is achieved.