Abstract:In this report, we demonstrate high spectral responsivity (SR) in MBE grown

We report on the deposition of Ga2O3 using microwave irradiation technique on III-nitride epi-layers. We also report on the first demonstration of a Ga2O3 device a visible blind deep -UV detector -with GaN-based heterostructure as the substrate. The film deposited in the solution medium, at < 200 o C, using a metalorganic precursor, was nanocrystalline. XRD confirms that as deposited film when annealed at high temperature turns polycrystalline β−Ga2O3. SEM shows the as-deposited film to be uniform, with a surface roughness of 4-5 nm, as revealed by AFM. Interdigitated metal semiconductor metal (MSM) devices with Ni/Au contact exhibited peak spectral response at 230 nm and a good visible rejection ratio. This first demonstration of a deep-UV detector on β − Ga2O3/III-nitride stack is expected to open up new possibilities of functional and physical integration of β − Ga2O3 and GaN material families towards enabling next generation high-performance devices by exciting band and heterostructure engineering. a) Corresponding author email: piyushj@iisc.ac.in

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We demonstrate zero-bias spectral responsivity in MBE-grown β-Ga 2 O 3 planar UV-C detector with good linearity up to optical power density of 4.6 mW cm %2. Devices with asymmetrical metal contacts were realized on 150 nm thick β-Ga 2 O 3 films on sapphire. The device exhibited a spectral responsivity of 1.4 mA W %1 at 255 nm under zero-bias condition, dark current <10 nA at 15 V and UV-to-visible rejection ratio >10 5 at 5 V. The demonstrated UV-C detector exhibited an estimated high detectivity of 2.0 ' 10 12 Jones at 1 V and were found to be very stable and repeatable, suggesting its potential use for focal plane arrays.

We demonstrate an InAlN/GaN-on-Si HEMT based UV detector with photo to dark current ratio > 10 7 . Ti/Al/Ni/Au metal stack was evaporated and rapid thermal annealed for Ohmic contacts to the 2D electron gas (2DEG) at the InAlN/GaN interface while the channel + barrier was recess etched to a depth of 20 nm to pinch-off the 2DEG between Source-Drain pads. Spectral responsivity (SR) of 34 A/W at 367 nm was measured at 5 V in conjunction with very high photo to dark current ratio of > 10 7 . The photo to dark current ratio at a fixed bias was found to be decreasing with increase in recess length of the PD. The fabricated devices were found to exhibit a UV-to-visible rejection ratio of >10 3 with a low dark current < 32 pA at 5 V. Transient measurements showed rise and fall times in the range of 3-4 ms. The gain mechanism was investigated and carrier lifetimes were estimated which matched well with those reported elsewhere.