Effect of Growth Pressure on PLD‐Deposited Gallium Oxide Thin Films for Deep‐UV Photodetectors

Abstract

Pulsed laser deposition (PLD) is used to grow ‐oriented single‐crystalline β‐gallium oxide (β‐Ga 2 O 3 ) thin films on c‐plane sapphire substrates by optimized growth temperature and pressure. The morphology and crystallinity of the thin films are examined using X‐ray diffraction and atomic force microscopy. The thin films are used as the semiconductor layer for metal–semiconductor–metal (MSM) photodetector (PD) devices with various electrode designs. The ultraviolet photodetectors are characterized under 250 nm illumination, showing a high current amplitude increase over dark current conditions that approaches three orders of magnitude at a 6 V bias for an optimized growth pressure of 1 × 10 −3 torr. The photodetectors' transient response is also measured, allowing for the defect analysis to be performed. A peak spectral responsivity of 30.45 A W −1 is measured at 250 nm incident illumination.