Observation of resonant tunneling action in ZnO/Zn0.8Mg0.2O devices

Device applications of transparent oxide semiconductors: Excitonic blue LED and transparent flexible TFT

“…However, emission properties are deteriorated in all the presently available p-type ZnO due to high-density acceptor doping. ZnO has another advantages because solid-solutions such as (Zn, Mg)O can be used for electron blocking layer, by which resonant tunneling diodes are fabricated and electron confinement effects are observed in ZnO/(Zn, Mg)O heterostructure devices [2,4,[33][34][35]. Nevertheless, we still think it is important to seek new materials because we wonder if stability and controllability of carrier concentration in ZnO will be able to meet with the requirements of practical devices.…”

Observation of Room Temperature Photoluminescence from Asymmetric CuGaO<SUB>2</SUB>/ZnO/ZnMgO Multiple Quantum Well <I>Structures</I>

“…[5][6][7][8][9] Ohtomo et al have grown ZnO/ZnMgO MQWs on lattice mismatched sapphire substrates using laser molecular beam epitaxy, but no photoluminescence (PL) was observed above 150 K. 7 10 In addition, the quantum confinement effects could not be observed in their MQWs through optical absorption spectroscopy, 10 presumably due to the inadequate quality of the grown structures. Krishnamoorthy et al 11 have reported size dependent quantum confinement effects by means of pulsed PL measurements at 77 K in ZnO/ZnMgO single quantum wells grown on sapphire substrates using the pulsed laser deposition. However, a significant improvement in the structural and optical characteristics of ZnO MQWs was accomplished when a lattice-matched substrate ScAlMgO 4 (SCAM) was used instead of sapphire, which was evident from the efficient photoluminescence 1 8 12 and distinct photon absorption features 13 at room temperature.…”

Effect of substrate temperature on residual stress of ZnO thin films prepared by ion beam deposition

“…[3] These properties of ZnO have attracted a great deal of attention for various technological applications such as UV light-emitters, piezoelectric transducers, and window material for flat-panel displays and efficient solar cells. [4][5][6] In addition, ZnO thin films belong to the class of transparent conductive oxides and have been studied extensively for transparent thin film transistors. [7] Various deposition methods have been used to prepare ZnO thin films, including metalorganic chemical vapor deposition, sol-gel techniques, radio frequency (RF) magnetron sputtering, pulsed laser deposition, and molecular beam epitaxy, spray pyrolysis etc., [8][9][10][11][12][13] RF magnetron sputtering deposition of those methods has been used more widely in industry due to the ability of large-area deposition and the high growth rate.…”