Electrical Properties and Microstructures of Ultraviolet Transparent Ga₂O₃ Thin Films

Abstract

The electrical and optical properties, and microstructures of 100 nm-thick Ga2O3 films fabricated on Al2O3(0001) substrates by a sputtering deposition were investigated. The partial pressure of oxygen was controlled and the substrate temperature was kept to be 500 °C during deposition. With increasing the oxygen partial pressure, the structures of the Ga2O3 films deposited on the substrates were observed to change from amorphous to crystalline (monoclinic β-type Ga2O3). The transmittance of the Ga2O3 films was measured to be more than 80 % at the visible and ultraviolet regions although the electrical resistivity was high. In order to obtain both low electrical resistivity and high transmittance at the ultraviolet regions, the addition of active dopant elements such as Sn into the Ga2O3 films would be required.

Recent advances in the growth of gallium oxide thin films employing various growth techniques—a review

“…In one report, Shigetoshi et al studied the electrical and optical properties of β-Ga 2 O 3 films (100 nm thick) on the sapphire (0001) substrate [217]. The substrate temperature and working pressure during deposition were kept at 500 • C and 0.03 Pa, respectively.…”

Method to Reduce the Contact Resistivity between Galinstan and a Copper Electrode for Electrical Connection in Flexible Devices

“…The volume resistivity of the oxide layer is estimated to be 10 6 Ωm, and the resistance of the oxide layer changes with the duration of exposure of the Ga-based LMs to air. The oxide layer also exhibits poor wettability for metallic materials. − , The Ga-based LMs and many solid metals (SMs) form alloys over time, − although some SMs such as stainless steel, nickel, and chromium do not form alloys easily, − and the Ga-based LMs with the oxide layer wet the alloy. − Previously, the LMs have been used as stretchable and deformable conductors in stretchable electronic devices, such as stretchable interconnects, , flexible sensors, , flexible antennas, , flexible actuators, devices to integrate chip light-emitting diodes (LEDs), , temperature sensors, , acceleration sensors, and thermoelectric generators . However, the high contact resistance of the oxide layer on the surface of the Ga-based LMs becomes a problem when the Ga-based LM is used in contact with rigid electronic components.…”

“…The oxide layer also exhibits poor wettability for metallic materials. [13][14][15][16][17][18]21 The Gabased LMs and many solid metals (SMs) form alloys over time, 22−32 although some SMs such as stainless steel, nickel, and chromium do not form alloys easily, 33−35 and the Gabased LMs with the oxide layer wet the alloy. 22−32 Previously, the LMs have been used as stretchable and deformable conductors in stretchable electronic devices, such as stretchable interconnects, 36,37 flexible sensors, 38,39 flexible antennas, 40,41 flexible actuators, 42 devices to integrate chip lightemitting diodes (LEDs), 43,44 temperature sensors, 45,46 acceleration sensors, 45 and thermoelectric generators.…”