Karmvir Singh

X-ray photoelectron spectroscopy investigations of band offsets in Ga0.02Zn0.98O/ZnO heterojunction for UV photodetectors

Here, we report the valence and conduction band offset measurements in pure ZnO and the Ga0.02Zn0.98O/ZnO heterojunction by X-Ray photoelectron spectroscopy studies for UV photodetector applications. For detailed investigations on the band offsets and UV photodetection behavior of Ga0.02Zn0.98O/ZnO heterostructures, thin films of pristine ZnO, Ga-doped ZnO (Ga0.02Zn0.98O), and heterostructures of Ga-doped ZnO with ZnO (Ga0.02Zn0.98O/ZnO) were deposited using a pulsed laser deposition technique. The deposited thin films were characterized by X-ray diffraction, atomic force microscopy, and UV-Vis spectroscopy. X-ray photoelectron spectroscopy studies were carried out on all the thin films for the investigation of valence and conduction band offsets. The valence band was found to be shifted by 0.28 eV, while the conduction band has a shifting of −0.272 eV in the Ga0.02Zn0.98O/ZnO heterojunction as compared to pristine ZnO thin films. All the three samples were analyzed for photoconduction behavior under UVA ...

Structural optical and electronic properties of Fe and Ga doped ZnO thin films grown using pulsed laser deposition technique

Band gap engineering in ZnO thin films have been subject of intensive studies. The thin films of 2 wt % Fe and 2 wt % Ga doped ZnO and undoped ZnO were deposited on glass substrate by pulse laser deposition technique. Structural, optical and electronic structure properties of these thin films were investigated by X- Ray diffraction (XRD), UV-Vis spectroscopy and X-ray absorption spectroscopy (XAS), respectively. XRD studies show that all the thin films are highly oriented along the c-axis and maintain the wurtzite structure. Out of plane lattice parameter in Ga doped is smaller while in Fe doped is larger, compared to undoped ZnO. The band gaps of doped films have been found to increase due to doping of the Ga and Fe ions. XAS studies across O K edges of doped thin films show that the conduction band edge structure probed via oxygen 1s to 2p transitions have modified significantly in Ga doped sample.

Structural and electrical properties of P doped ZnO films

Structural, electronic and electrical properties of Phosphorus doped ZnO thin films deposited using pulsed laser deposition technique, on P-type Si (111) substrate are studied. X-ray diffraction measurements shows that undoped ZnO and Phosphorus doped ZnO films oriented along c-axis and maintains wurtzite crystalline symmetry. The change in grain size occurs by Phosphorus doping, which can be correlated to stress comes due to presence of Phosphorus. The changes in electronic structure has been observed by Phosphorus doping in ZnO thin films, which is understood from X-ray absorption spectroscopy. Hall measurements shows n-type behavior of Phosphorus doped ZnO samples.Structural, electronic and electrical properties of Phosphorus doped ZnO thin films deposited using pulsed laser deposition technique, on P-type Si (111) substrate are studied. X-ray diffraction measurements shows that undoped ZnO and Phosphorus doped ZnO films oriented along c-axis and maintains wurtzite crystalline symmetry. The change in grain size occurs by Phosphorus doping, which can be correlated to stress comes due to presence of Phosphorus. The changes in electronic structure has been observed by Phosphorus doping in ZnO thin films, which is understood from X-ray absorption spectroscopy. Hall measurements shows n-type behavior of Phosphorus doped ZnO samples.