Design considerations for InGaAlP lasers and light-emitting diodes on high-index GaAs substrates for the yellow and green spectral range

We consider the impact of strain and substrate orientation on the conduction band (CB) and valence band (VB) energies in (Al,Ga,In)P materials. We show that applying tensile strained GaP-rich insertions as barriers in lattice-matched heterostructures grown on high-index GaAs substrates, like (211), (322), and (111) ones, allows to overcome the main problem of (Al,Ga,In)P materials, namely the cross-over of the G and X minima of the CB in (In,Ga,Al)P alloy at similar to 55% AlInP content which hinders the possibility to extend the spectral range of the devices towards shorter wavelengths. Adding GaP-enriched insertion for structures grown on the (111) substrate allows to shift the X minimum upwards forming a potential barrier for electrons escaping the active region. Both the initial energy of the CB X minimum of GaP, the highest among III-V binaries, and the tensile strain help. For other orientations the effect is reduced or is even of opposite sign due to the splitting of the X band minimum upon applied strain. For high strain an impact on the G and L minima in the barrier insertion are to be considered, as both minima are strongly shifted downwards once the strained insertion is parallel to the (111) plane. Admixture of AlP helps to push the G and L minima to higher energies (additional 1 eV for L minimum for AlP compared to GaP) even at the expense of a smaller increase of the X band-induced barrier. Experimental results confirm the predictions, revealing lasing at 599 nm at room temperature. We show that with proper substrate orientation and the composition of the strained barriers one can strongly modify and tune the CB minima extending the spectral rage of InGaAlP lasers to wavelengths shorter than similar to 570-590 nm at room temperature.