Near ultraviolet luminescence of Be doped GaN grown by reactive molecular beam epitaxy using ammonia

Abstract

Be doped GaN films grown by reactive molecular beam epitaxy (MBE) are investigated. The room temperature photoluminescence spectrum of the films that were studied shows features in the 390–420 nm range, similar to those observed in Mg doped GaN films, and indicates that Be can form acceptor states about 250 meV above the valence band of GaN. This is in contrast to previous works on GaN:Be films where the only luminescence feature seen was a broad peak centered at 2.16 eV (560 nm). Hot probe measurement indicates p-type conduction for GaN:Be doped films without any postgrowth annealing. Current–voltage measurements of fabricated mesas of MBE grown layers, consisting of a GaN:Be doped film grown over a Si doped GaN layer, show p–n diodelike rectification. A weak electroluminescence at 380–390 nm is observed when the device is driven with a pulsed current of 600 mA.

Doping of AlGaN Alloys

“…Experimental results about Be are inconclusive: Brandt et al have reported high levels of p-type doping using Be in MBE, provided oxygen is present as a co-dopant. 52,53 This result is difficult to understand based on equilibrium thermodynamics, as pointed out by Bernardini et al 50 Other work has indicated Be indeed acts as an acceptor; results about the ionization energy are based on luminescence, with Salvador et al finding a relatively large ionization energy (250 meV), 54 Ronning et al finding 150 meV, 55 and Sánchez et al deriving a much smaller value (90 meV). 56 To our knowledge, experimental studies of other acceptor impurities have only been performed using ion implantation (see, e.g., Ref.…”

Ion implanted dopants in GaN and AlN: Lattice sites, annealing behavior, and defect recovery

“…For such applications it is necessary to dope these semiconductors, and, commonly, Si or O are used as donors, 20,21 and Mg, Be, Zn, or Ca as acceptors. 17,[22][23][24][25][26][27] The incorporation of dopants into gallium nitride ͑GaN͒ and aluminum nitride ͑AlN͒ by diffusion is very difficult due to their high thermal stability. [28][29][30] Moreover, the realization of lateral doping structures during film growth is impossible.…”

First-principles studies of beryllium doping of GaN

“…This conclusion is in agreement with the assessment of Bernardini et al 6 Experiments on Be incorporation in GaN are still scarce. Incorporation of Be in GaN has so far been performed during MBE growth [7][8][9][10][11][12][13][14][15] and using ion implantation. 16,17 The earliest report of Be doping was by Ilegems and Dingle, 47 who incorporated Be during vapor growth of GaN.…”

“…[7][8][9][10][11][12][13][14][15] These experimental studies have involved both wurtzite and cubic phases of GaN; the cubic phase can be obtained by growth on cubic substrates, under appropriately tailored conditions. Another technique for Be incorporation that has been attempted is ion implantation.…”