Laser CVD Growth of Uniquely < 010 >-oriented beta-Ga2O3 Films on Quartz Substrate with Ultrafast Photoelectric Response

The oriented growth of ss-Ga2O3 films has triggered extensive interest due to the remarkable and complex anisotropy found in the ss-Ga2O3 bulks. Remarkable properties, including stronger solar-blind ultraviolet (SBUV) absorption, better mobility, and higher thermal conductivity, are usually observed along <010> direction as compared to other low-index axes. So far, <010>-oriented ss-Ga2O3 film growth has been hindered by the lack of suitable substrates and higher surface energy of the (010) crystal plane. Herein, the first growth of uniquely <010>-oriented ss-Ga2O3 films on quartz substrates by laser chemical vapor deposition (LCVD) are reported. By investigating the effects of deposition temperature (Tdep) and O-2 flow rate (RO2) on the growth of ss-Ga2O3 films, it is found that the formation of <010> orientation is closely related to the higher stability of oxygen close-packed planes under O-rich condition. As a result, a grain size of up to similar to 2 mu m and a deposition rate of up to similar to 40 mu m h-1 are obtained. Metalsemiconductor-metal (MSM) type detector based on <010>-oriented ss-Ga2O3 film exhibits ultra-fast response speed, 1-2 orders of magnitude higher than those of most detectors based on ss-Ga2O3 films with other orientations.