Sn Doping Induced Interfacial Barrier Height Tailoring in Ga2O3 Deep-Ultraviolet Photodetector
The optimization of device performance through tunable elemental doping is a critical aspect of semiconductor engineering. This study employs plasma-enhanced chemical vapor deposition to fabricate Sn-doped Ga2O3 films with Sn concentrations ranging from 0 to 1.14 at.%. The oxygen vacancy (OII) concentration is found to modulate the conductivity and the atypical Schottky-type junction behavior at the Ti/Sn-Ga2O3 interface, thereby influencing carrier transport and the detection performance of Au/Ti/Sn-Ga2O3/Ti/Au photodetectors. At an OII concentration of 38.88%, the interfacial Schottky barrier height decreases to 0.54 eV, facilitating electron tunneling and yielding a responsivity of 1880 mA/W. Conversely, a reduced OII concentration of 30% reinforces the barrier height to 0.70 eV, restricting dark current to 28.4 pA while improving detectivity to 1.44×10^13 Jones and the photo-to-dark current ratio to 3.42×10^4. These results underscore the trade-off between doping concentration and performance optimization, demonstrating the potential of interface engineering in regulating electronic transport and device performance.