Effects of annealing temperature on a ZnO thin film-based ultraviolet photodetector

In this paper, the effects of annealing temperature on the performance of a ZnO thin film-based Metal-Semiconductor-Metal (MSM) type ultraviolet (UV) photodetector is reported. ZnO thin films were grown on a glass substrate using the Pulsed Filtered Cathodic Vacuum Arc Deposition (PFCVAD) technique at room temperature and after the deposition process the samples were annealed at 400, 450 and 550 °C in air condition to investigate the annealing effect on the structural, electrical, and optical properties of the photodetector. ZnO thin films which have grains in nanometer range has an increasing in the diameter of grains from 10.5 to 18.3 nm as a function of annealing temperature results in a red shift in the cut-off wavelength of the photodetector from 3.25 eV (381 nm) to 3.23 eV (383 nm). It is demonstrated that the sensitivity and the speed (rise/fall times) of the ZnO thin film based MSM photodetectors enhances with increasing post growth annealing temperature of ZnO thin film due to the increase in the absorption coefficient and the decrease of the total area of the grain boundaries due to the larger grain sizes formation in ZnO thin films with increasing thermal annealing temperature.

(Au, Ag)/Al0.08In0.08Ga0.84N/ (Au, Ag) Metal-semiconductor-metal (MSM) Photodetectors

Metal-semiconductor-metal (MSM) photodetectors (PDs) based on gold and silver (Au, Ag)/Al0.08In0.08Ga0.84N (commercial sample)/ (Au, Ag) have been fabricated and characterized. The effect of annealing temperature of As deposit, 400, 500, and 600 0C for 30 min on the topography and electrical properties of Au contact on Al0.08In0.08Ga0.84N thin film have been characterized and optimized using Current-Voltage (I-V) characteristic. Schottky barrier height (SBH) and ideality factor (n) of Au/ Al0.08In0.08Ga0.84N interface were 1.223 eV and 1.773 at 50 0C annealing temperature for 30 min respectively, and it is found that contact has a high-quality surface. Also, with the same procedure, the effect of annealing time of 15, 30, 45 minutes, and 1 hour have been studied and optimized. The results revealed that the best annealing time is 30 min which has the highest SBH. Au contact compared with Ag contact used to first time as best our knowledge with the optimal condition to select the best metal for MSM photodetectors (PDs). The ideal characterization of Au, Ag/AlInGaN/Au, Ag MSMPDs on Si substrate depend on responsivities of 0.201 and 0.153 A W-1, quantum efficiencies of 71% and 57%, and NEPs of 3.55×10-4 and 1.45×10-3W-1, respectively have been also studied compared. The height SBH and QE for the samples grown on Si was at Au contact which proposed to use in such optoelectronic devices.

Modulation of light absorption in flexible GeSn metal–semiconductor–metal photodetectors by mechanical bending

We have demonstrated flexible GeSn metal–semiconductor–metal (MSM) photodetectors (PDs) by exploring the effect of mechanical strain on their optoelectronic properties.