Atomic‐Layer‐Ti‐Doped Ga₂O₃ Thin Films with Tunable Optical Properties and Wide Ultraviolet Optoelectronic Responses

Abstract

Doping and alloying in Ga2O3 to tune electronic and photonic behaviors is still urgent but challenging, whereas Ga2O3 has shown great promise in deep‐ultraviolet (DUV) photodetectors and functional high‐power devices. Herein, atomic‐layer‐Ti‐doped/incorporating Ga2O3 (TGO) thin films with tailored optical properties in the UV region from 200 to 400 nm are described. The Ti content in amorphous TGO thin films is controlled and adjusted up to 11 at% during a plasma‐enhanced atomic layer deposition (PE‐ALD) process. The composition‐dependent optical constants of both amorphous and polycrystalline TGO thin films are analyzed in the wavelength region of 200–800 nm through spectroscopic ellipsometry (SE) with a point‐by‐point fitting method. An obvious bandgap tuning effect and redshifted absorption edges are observed in the transmittance spectra of TGO thin films with increasing Ti concentration. Moreover, composition‐dependent optical constants and wide absorption are also verified by the significant and broadened DUV photoelectronic responses of TGO‐based photodetectors. It is believed that this work will help in understanding the DUV optical constants and bandgap transitions of TGO thin films used for functional optical devices in the UV region below 400 nm.

Toward Broadband Photodetection: Band Alignment and Interlayer Charge Transfer in 2D Transition Metal Dichalcogenides/3D-Ga2O3 Hybrid-Dimensional Heterostructures

“…The deposition cycle comprised four stages: TEG pulsing (0.5 s), Ar purging (10.0 s), O plasma processing (18.0 s), and Ar purging (20.0 s). In our previous research, we confirmed that the as-deposited Ga 2 O 3 films were amorphous, as they did not exhibit any X-ray diffraction signals or Raman scattering peaks . Additionally, through transmission electron microscopy (TEM) and spectroscopic ellipsometry (SE), we established a deposition rate of 0.4 Å per cycle .…”

“…In our previous research, we confirmed that the as-deposited Ga 2 O 3 films were amorphous, as they did not exhibit any X-ray diffraction signals or Raman scattering peaks. 58 Additionally, through transmission electron microscopy (TEM) and spectroscopic ellipsometry (SE), we established a deposition rate of 0.4 Å per cycle. 40 For this experiment, we employed 300 deposition cycles to achieve Ga 2 O 3 films with a thickness of approximately 10 nm.…”

Ga2O3–MXene Nanowire Networks with Enhanced Responsivity for Deep-UV Photodetection

“…The materials for constructing UV photodetectors are ultrawide-band gap semiconductors, such as AlGaN, Ga 2 O 3 , and diamond . Ga 2 O 3 is a promising semiconductor material as it possesses an ultrahigh band gap of 4.2–5.2 eV for photodetectors. , However, the practical application of Ga 2 O 3 is still limited by its defects, such as low conductivity and long response time.…”

“…6 Ga 2 O 3 is a promising semiconductor material as it possesses an ultrahigh band gap of 4.2−5.2 eV for photodetectors. 7,8 However, the practical application of Ga 2 O 3 is still limited by its defects, such as low conductivity 2 and long response time.…”

Preparation of Sn-doped Ga2O3 thin films and their solar-blind photoelectric detection performance

“…Therefore, Ga 2 O 3 thin film-based solar-blind detector has the most commercial application prospect [6] . The preparation methods of Ga 2 O 3 thin films include metal-organic chemical vapor deposition (MOCVD) [7−9] , molecular beam epitaxy (MBE) [10,11] , atomic layer deposition (ALD) [12−14] , pulse laser deposition (PLD) [15,16] , plasma-enhanced chemical vapor deposition (PECVD) [17] , radio frequency magnetron sputtering (RFMS) [18−21] and so on. The MOCVD, MBE, PLD and ALD methods can strictly control the thickness, composition, and doping concentration for high quality Ga 2 O 3 thin films, but the equipment is complicated or the growth rate is relatively slow with a high production cost.…”