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Proceedings Paper

Continuous visible-light emission at room temperature in Mn-doped GaAs and Si light-emitting diodes (Presentation Recording)
Author(s): Masaaki Tanaka; Pham Nam Hai; Le Duc Anh
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Paper Abstract

We demonstrate visible-light electroluminescence due to d-d transitions in GaAs:Mn based light emitting diodes (LEDs) [1][2]. We prepared p+n junctions with a p+GaAs:Mn layer. At a reverse bias voltage (-3 to -6V), holes are injected from the n-type layer to the depletion layer and accelerated by the intense electric field, and excite the d electrons of Mn in the p+GaAs:Mn layer by impact excitations. We observe visible-light emission E1 = 1.89eV and E2 = 2.16eV, which are exactly the same as the 4T1 -> 6A1 and 4A2 -> 4 T1 transition energy of Mn. Furthermore, by utilizing optical transitions between the p-d hybridized orbitals of Mn atoms doped in Si, we demonstrate Si-based LEDs that continuously emit reddish-yellow visible light at room temperature. The Mn p-d hybrid states are excited by hot holes that are accelerated in the depletion layers of reverse biased Si pn junctions. Above a threshold reverse bias voltage of about -4V, our LEDs show strong visible light emission with two peaks at E1 = 1.75eV and E2 = 2.30eV, corresponding to optical transitions from the t-a (spin-down anti-bonding) states to the e- (spin-down non-bonding) states, and from the e- to the t+a (spin-up anti-bonding) states. The internal quantum efficiency of the E1 and E2 transitions is 3-4 orders of magnitude higher than that of the indirect band-gap transition [3]. [1] P. N. Hai, et al., APL 104, 122409 (2014). [2] P. N. Hai, et al., JAP 116, 113905 (2014). [3] P. N. Hai, et al., submitted.

Paper Details

Date Published: 5 October 2015
PDF: 1 pages
Proc. SPIE 9551, Spintronics VIII, 955118 (5 October 2015); doi: 10.1117/12.2191840
Show Author Affiliations
Masaaki Tanaka, The Univ. of Tokyo (Japan)
Pham Nam Hai, The Univ. of Tokyo (Japan)
Le Duc Anh, The Univ. of Tokyo (Japan)

Published in SPIE Proceedings Vol. 9551:
Spintronics VIII
Henri-Jean Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi, Editor(s)

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