Fabrications and application of single crystalline GaN for high-performance deep UV photodetectors

Abstract

High-quality single crystalline Gallium Nitride (GaN) semiconductor has been synthesized using molecule beam epitaxy (MBE) technique for development of high-performance deep ultraviolet (UV) photodetectors. Thickness of the films was estimated by using surface profile meter and scanning electron microscope. Electronic states and elemental composition of the films were obtained using Raman scattering spectroscopy. The orientation, crystal structure and phase purity of the films were examined using a Siemens x-ray diffractometer radiation. The surface microstructure was studied using high resolution scanning electron microscopy (SEM). Two types of metal pairs: Al-Al, Al-Cu or Cu-Cu were used for interdigital electrodes on GaN film in order to examine the Schottky properties of the GaN based photodetector. The characterizations of the fabricated prototype include the stability, responsivity, response and recovery times. Typical time dependent photoresponsivity by switching different UV light source on and off five times for each 240 seconds at a bias of 2V, respectively, have been obtained. The detector appears to be highly sensitive to various UV wavelengths of light with very stable baseline and repeatability. The obtained photoresponsivity was up to 354 mA/W at the bias 2V. Higher photoresponsivity could be obtained if higher bias was applied but it would unavoidably result in a higher dark current. Thermal effect on the fabricated GaN based prototype was discussed.

Insights into the formation mechanism of two-dimensional lead halide nanostructures

“…The reflexes in the XRD fit well with the literature for the perovskite material. 10 To discuss the thickness and crystal structure of the structures powder X-ray diffraction as well as atomic force microscopy measurements were carried out. Figure S6 shows powder XRDs of PbI2, PbBr2 and PbCl2.…”

ZnO Film UV Photodetector with Enhanced Performance: Heterojunction with CdMoO4 Microplates and the Hot Electron Injection Effect of Au Nanoparticles

“…High sensitivity, high signal‐to‐noise ratio, high spectral selectivity, high speed, and high stability are required for high performance UV PDs . Selecting appropriate active materials is of great importance for fabricating PDs with high performance …”

Design of a Four-Branch Optical Power Splitter Based on Gallium-Nitride Using Rectangular Waveguide Coupling for Telecommunication Links

“…where P out and P in are the total optical output power and the optical input power, respectively. The amount of power imbalance in a splitter is given by the ratio of maximum output power to the minimum output power as defined in (16).…”

“…where P max is the highest optical power and P min is the lowest optical power at the four output ports. By using (15) and (16), excess loss and power imbalance of the splitter across 100 nm spectrum of wavelength were calculated at the best geometrical value of the proposed power splitter. The results are presented in Figures 9 and 10 accordingly.…”

“…So far, the development of III-nitride based photonic devices has been focused on the light source [13][14][15] and photodetectors [16]. However, besides being developed as a light source and photodetectors, III-nitride based waveguide device design has also been developed.…”