Characterization of MG-doped InGaN and InALN alloys grown by MBE for solar applications

In
x
Ga
1-x
N and In
x
Al
1-x
N alloys are grown via MBE on sapphire substrates. A hole concentration of 7.7×10
¹⁷
cm
⁻³
is achieved on Mg-doped In
0.04
Ga
0.96
N. When x≫0.11, the Hall samples exhibit strong n-type polarity, whereas p-type polarity is confirmed by hot probe measurement for all Mg-doped InGaN and InAlN samples. Single p-i-n junction solar cells made of the same In
x
Ga
1-x
N alloy composition are developed. Upon illumination by a 325 nm laser, V
oc
is measured at 2.5 V with a fill factor of 61% for all-GaN cell. Clear photo-responses are also observed in InGaN cells with 0.2 and 0.3 Indium content when illuminated by focused outdoor sunlight.