Modulated Al2O3-Alloyed Ga2O3 Materials and Deep Ultraviolet Photodetectors

To modulate the cutoff wavelength of the metal-semiconductor-metal deep ultraviolet photodetectors (MSM DUV-PDs), the aluminum content of the aluminium oxide-alloyed gallium oxide (Ga
₂
O
₃
:Al
₂
O
₃
) absorption layers was deposited using radio frequency (RF) magnetron cosputter system with dual targets, in which the Ga
₂
O
₃
target was sputtered with an RF power of 100 W and the Al
₂
O
₃
target sputtered with various RF powers. The optical bandgap energy of the Ga
₂
O
₃
:Al
₂
O
₃
films increased with an increase of the Al content deposited with a larger sputtered RF power of the Al
₂
O
₃
target. In view of the suppression effect of the oxygen vacancy and the defect by the more Al-O bonds in the Ga
₂
O
₃
:Al
₂
O
₃
absorption layer, the noise performances and the detectivity of the MSM DUV-PDs were improved. For depositing the Al atomic percentage of 5.9% in the Ga
₂
O
₃
:Al
₂
O
₃
absorption layer, the resulting MSM DUV-PDs revealed the cutoff wavelength of 230 nm, the noise equivalent power of 2.80 × 10
^-12
W, and the detectivity of 1.37 × 10
¹¹
cmHz0.5W
^-1
. Furthermore, the dominant low-frequency noise source was the flicker noise.