Growth of n- and p-type ZnTe semiconductors by intrinsic doping

Using intrinsic doping, n- and p-type ZnTe thin films have been electrodeposited (ED) on glass/fluorine-doped tin oxide (FTO) conducting substrate in aqueous solutions of ZnSO4·7H2O and TeO2. The intrinsic doping was achieved by simply varying the deposition potential. The films have been characterised for their structural, optical, electrical, morphological and compositional properties using X-ray diffraction (XRD), optical absorption, photoelectrochemical (PEC) cell measurements, scanning electron microscopy and energy-dispersive X-ray analysis techniques, respectively. The XRD results reveal that the electroplated films are polycrystalline and have hexagonal crystal structures. Optical absorption measurements have been used for the bandgap determination of as-deposited and heat-treated ZnTe layers. The bandgap of the as-deposited ZnTe films are in the range (1.70–2.60) eV depending on the deposition potential. PEC cell measurements reveal that the ED-ZnTe films have both n- and p-type electrical conductivity. Using the n- and p-type ZnTe layers, a p-n homo-junction diode with device structure of glass/FTO/n-ZnTe/p-ZnTe/Au was fabricated. The fabricated diode showed rectification factor of 102, ideality factor of 2.58 and threshold voltage of ~0.25 V.