Phosphorus doped ZnO light emitting diodes fabricated via pulsed laser deposition

Abstract

ZnO-based light emitting diodes were fabricated on c-plane sapphire using ZnO:P∕Zn0.9Mg0.1O∕ZnO∕Zn0.9Mg0.1O∕ZnO:Ga p-i-n heterostructures. The p-i-n heterojunction diodes are rectifying and show light emission under forward bias. The electroluminescence spectra shows deep level emission at low bias, but near band edge ultraviolet emission at high voltage bias. A decrease in leakage currents in as-fabricated structures was achieved via low temperature oxygen annealing.

Shallow and Deep Centers in As-Grown and Annealed MgZnO/ZnO Structures with Quantum Wells

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] p-n junction diodes, HJ, and QWbased diodes have been demonstrated and used to fabricate prototype blue LEDs. 13,14 However, controlled p-type doping of the structures still presents a problem, while deep-trap spectra, and electrical and optical properties of MgZnO/ZnO QWs are not known in detail. In particular, it is not understood why some structures show good p-type conductivity upon annealing whereas others do not.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Good-quality wurtzite single layers, heterojunctions (HJs), and quantum wells (QWs) with Mg mole fractions from 0% to 50% can be grown on ZnO or sapphire substrates by molecularbeam epitaxy or pulsed laser deposition (PLD). The bandgap in such films, HJs, and QWs can be tailored in the range from 3.3 eV to 4 eV, n-type doping can be achieved by adding group III impurities such as Ga or Al, while p-type doping can be produced by the addition of group V impurities, such as N, P, and Sb, with subsequent thermal annealing.…”

Electronic and Optical Properties of Mg x Zn1−x O and Be x Zn1−x O Quantum Wells

“…Several hybrid LEDs have been proposed, with either n-type ZnO 7-10 or n-type MgZnO layers, [11][12][13] using III-V nitrides for the p-layers. Fully ZnO-based LEDs presented in the recent literature include, e.g., bulk p-i-n ZnO structures, 14 bulk p-n ZnO structures, [15][16][17][18][19][20][21][22][23][24][25][26][27] MgZnO/CdZnO double heterostructures, 8 p-n MgZnO structures, 28 ZnO/MgZnO single quantum wells (SQWs), [29][30][31] and ZnO/MgZnO multiple quantum wells (MQWs). 32 The demonstration of the first BeZnO/ZnO MQW LEDs 33 and lasers 34 has stimulated significant experimental and theoretical work also on BeZnO, [35][36][37][38] an interesting alternative to MgZnO because it crystallizes in the wurtzite phase over its entire composition range.…”

Composition Dependence on Structural and Optical Properties of MgxZn1-xO Thin Films Prepared by Sol-Gel Method

“…Figure 5 shows the residual stress and the bond length as a function of the content ratio of magnesium acetate tetrahydrate to zinc acetate dihydrate. The residual stress σ in the Mg x Zn 1-x O thin films can be expressed as 26 (2) where C ij are elastic stiffness constants for ZnO (C 11 = 207.0 GPa, C 33 = 209.5 GPa, C 12 = 117.7 GPa, and C 13 = 106.1 GPa). The c and the c 0 are the lattice parameters of the ZnO thin films and of the strain-free ZnO, respectively.…”

“…[1][2][3][4][5] In particular, its large exciton binding energy of 60 meV, 6 which is larger than the thermal energy at room temperature (RT), allows excitons to play important roles at RT and ensures efficient lasing even at RT. 7 In addition, its high thermal and chemical stability with the possibility of using the wet processing has led to ZnO-based oxide semiconductor as an alternative material to nitride semiconductors.…”