Impact of ZnPc molecular orientation over the transitions in GaAs and its subsequent effects in ZnPc/GaAs stacked thin film structures

The Quantum confinement effect plays a fundamental role in governing the opto-electrical properties of thin films. In general, it is processed in the form of a strained multilayer structure. Here, an alternatively stacked ZnPc/GaAs multilayer structure has been fabricated through thermal evaporation technique. Its structural and optical properties were investigated with the function of variable ZnPc thickness. In the structural aspect, the crystallinity of GaAs has a dependence on the molecular orientation of ZnPc. It is identified that the transformation of the crystalline nature of GaAs phase is dependant on the vertical or horizontal orientation of ZnPc molecules. The transformation of GaAs phase shows an effective change in the absorption of ZnPc implied by the shift in the absorption edge from 400 nm to 500 nm. Photoluminescence confirmed that the multilayer structure with a parallel orientation of ZnPc shows the least radiative recombination than the other films. •The orientation of ZnPc molecules has influences on changes in crystallinity of GaAs.•Transformation of GaAs crystallinity helps to widen the absorption range of hybrid structure.•Least carrier recombination rate in hybrid structure occurred due to the parallel orientation of ZnPc molecules.