||Aluminum gallium nitride (AlGaN) is the most commonly used material for deep ultraviolet light emitting-diodes (DUV LEDs, emission wavelength < 290 nm). However, the external quantum efficiencies (EQEs) of DUV LEDs rarely reach 10 %, despite years of research efforts. The main reason is the extremely high activation energies of conventional acceptors in p-type AlxGa1-xN (170 – 510 meV). This intrinsic drawback subsequently results in low hole injection efficiency, and accordingly the conductivity of p-AlxGa1-xN. To overcome the difficulty, we employ boron nitride (BN) as the alternative to p-type AlGaN. BN is reported to exhibit much lower acceptor activation energy than AlGaN, in addition to her high chemical and thermal stability. These are attractive merits for the applications in DUV LEDs. To evaluate the electrical properties of p-type BN (p-BN), we systematically characterized p-BN with Hall measurements using different metal electrodes, annealing conditions, growth pressure, and V/III ratios with the intention to achieve ohmic contact on the two-dimensional layer. It is found that adding a 3-nm InGaN contact layer on the surface, or reducing the V/III ratio, can effectively reduce the contact resistance of p-BN.|
|| The electromagnetic spectrum , Available at: https://xpfamilysupport.org/learn/what-is-uv/|
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