Barthel Armin, Roberts Joseph, Napari Mari, Frentrup Martin, Huq Tahmida, Kovács András, Oliver Rachel, Chalker Paul, Sajavaara Timo, Massabuau Fabien
Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK.
School of Engineering, The University of Liverpool, Liverpool L69 3GH, UK.
Micromachines (Basel). 2020 Dec 20;11(12):1128. doi: 10.3390/mi11121128.
The suitability of Ti as a band gap modifier for α-GaO was investigated, taking advantage of the isostructural α phases and high band gap difference between TiO and GaO. Films of (Ti,Ga)O were synthesized by atomic layer deposition on sapphire substrates, and characterized to determine how crystallinity and band gap vary with composition for this alloy. We report the deposition of high quality α-(TiGa)O films with x = 3.7%. For greater compositions the crystalline quality of the films degrades rapidly, where the corundum phase is maintained in films up to x = 5.3%, and films containing greater Ti fractions being amorphous. Over the range of achieved corundum phase films, that is 0% ≤ x ≤ 5.3%, the band gap energy varies by ∼270 meV. The ability to maintain a crystalline phase at low fractions of Ti, accompanied by a modification in band gap, shows promising prospects for band gap engineering and the development of wavelength specific solar-blind photodetectors based on α-GaO.
利用TiO和GaO的同构α相以及高带隙差异，研究了Ti作为α-GaO带隙调节剂的适用性。通过原子层沉积在蓝宝石衬底上合成了(Ti,Ga)O薄膜，并对其进行表征，以确定该合金的结晶度和带隙如何随成分变化。我们报道了x = 3.7%的高质量α-(TiGa)O薄膜的沉积。对于更高的成分，薄膜的结晶质量迅速下降，其中在x = 5.3%以下的薄膜中保持刚玉相，而含有更高Ti分数的薄膜是非晶态的。在所获得的刚玉相薄膜范围内，即0%≤x≤5.3%，带隙能量变化约270 meV。在低Ti分数下保持结晶相并伴有带隙变化的能力，为带隙工程以及基于α-GaO的波长特定日盲光电探测器的开发展示了广阔前景。
