Surface nanopatterning of amorphous gallium oxide thin film for enhanced solar-blind photodetection

Abstract

Gallium oxide is an ultra-wide band gap semiconductor (Eg > 4.4 eV), best suited intrinsically for the fabrication of solar-blind photodetectors. Apart from its crystalline phases, amorphous Ga2O3 based solar-blind photodetector offer simple and facile growth without the hassle of lattice matching and high temperatures for growth and annealing. However, they often suffer from long response times which hinders any practical use. Herein, we report a simple and cost-effective method to enhance the device performance of amorphous gallium oxide thin film photodetector by nanopatterning the surface using a broad and low energy Ar+ ion beam. The ripples formed on the surface of gallium oxide thin film lead to the formation of anisotropic conduction channels along with an increase in the surface defects. The defects introduced in the system act as recombination centers for the charge carriers bringing about a reduction in the decay time of the devices, even at zero-bias. The fall time of the rippled devices, therefore, reduces, making the devices faster by more than 15 times. This approach of surface modification of gallium oxide provides a one-step, low cost method to enhance the device performance of amorphous thin films which can help in the realization of next-generation optoelectronics.

Laser CVD Growth of Uniquely <010>‐oriented β‐Ga2O3 Films on Quartz Substrate with Ultrafast Photoelectric Response

“…[ 62 ] As shown in Figure S12 (Supporting Information), the <010>‐oriented β‐Ga 2 O 3 films were in Schottky‐type contact with Pt electrodes, exhibiting slight rectifying behavior. [ 6 ] Typically, the Schottky‐type devices present a much faster response speed but lower responsivity than the Ohmic‐type devices. [ 63 ] Therefore, the Schottky contact caused by the unique surface morphology of <010>‐oriented β‐Ga 2 O 3 film also contributed to such an ultrafast response.…”

Topological Bi2Se3/n-GaN Hybrid Structure for Enhanced and Self-Powered UV Photodetectors

“…The transient photoresponse of each PD device shows the enhancement in photocurrent with a rise in the applied bias voltage as more photogenerated charge carriers reach their respective electrodes. The time-resolved photoluminescence (TRPL) measurements in which the decay time of charge carriers is smaller for Bi 2 Se 3 /n-GaN is shown in the TRPL plot in Figure S5 . Here, the photocurrent becomes maximum instantly and is then stable until the light is switched off.…”

“…The time-resolved photoluminescence (TRPL) measurements in which the decay time of charge carriers is smaller for Bi 2 Se 3 /n-GaN is shown in the TRPL plot in Figure S5. 61 Here, the photocurrent becomes maximum instantly and is then stable until the light is switched off. This sharp transition in photocurrent reveals that the device response is fast and stable.…”

Interfacial-Mixing and Band Engineering Induced by Annealing of CdS and a-Ga2O3 n–n-Type Thin-Film Heterojunction and Its Impact on Carrier Dynamics for High-Performance Solar-Blind Photodetection

“…Figure b shows temporal response of the devices for repeated switching on and off of the incident UV-C light. Rise time of the device is calculated as the time taken to go from 10 to 90% of the maximum photocurrent once the incident light is switched on, while the fall time is calculated as the time taken for the device to go from 90 to 10% of the maximum photocurrent once the incident light is switched off . The rise time of the devices reduces from 1.35 to 0.38 s upon annealing while the fall time reduces from 2.87 s to about 0.75 s for the pristine and annealed devices, respectively.…”

“…Rise time of the device is calculated as the time taken to go from 10 to 90% of the maximum photocurrent once the incident light is switched on, while the fall time is calculated as the time taken for the device to go from 90 to 10% of the maximum photocurrent once the incident light is switched off. 34 The rise time of the devices reduces from 1.35 to 0.38 s upon annealing while the fall time reduces from 2.87 s to about 0.75 s for the pristine and annealed devices, respectively. Thus, the annealed devices with a diffuse interface show a lower dark current, higher photoresponse, and faster speed as compared to the pristine devices with a sharp interface.…”