Optical Properties of Hafnium Doped Gallium Oxide Thin Films

Gallium Oxide (Ga₂0₃), an ultra-wide-bandgap semiconductor, is a promising material for high power electronic devices and solar blind detectors [1,2]. However intrinsic Ga₂0₃ exhibits too large of a resistivity for device applications. To overcome this challenge, Hafnium (Hf) can be introduced as a n-type dopant, however current work has only focused on single crystal Hf: Ga₂0₃ [3,4]. 

In this work we present the optical properties of Hf: Ga₂0₃ thin films fabricated by RF reactive sputter deposition. Initial results show Hf incorporation increases the index of refraction of the material while minimally altering the band gap. 

Citations 

1. Higashiwaki, Masataka, et al. “State-of-the-art technologies of Gallium Oxide Power Devices.” Journal of Physics D: Applied Physics, vol. 50, no. 33, 2017, p. 333002, https://doi.org/10.1088/1361-6463/aa7aff.  

1. Ji, Zhenguo, et al. “Gallium oxide films for Filter and solar-blind UV detector.” Optical Materials, vol. 28, no. 4, 2006, pp. 415–417, https://doi.org/10.1016/j.optmat.2005.03.006. 

1. Chmielewski, Adrian, et al. “Atomic-scale characterization of structural and electronic properties of HF doped β-ga2o3.” Applied Physics Letters, vol. 119, no. 17, 2021, https://doi.org/10.1063/5.0062739.  

1. Saleh, Muad, et al. “Degenerate doping in β-ga2O3 single crystals through hf-doping.” Semiconductor Science and Technology, vol. 35, no. 4, 2020, https://doi.org/10.1088/1361-6641/ab75a6.