Comment on

• Solar-energy conversion and light emission in an atomic monolayer p-n diode.

  Pospischil A, Furchi MM, Mueller T. Pospischil A, et al. Nat Nanotechnol. 2014 Apr;9(4):257-61. doi: 10.1038/nnano.2014.14. Epub 2014 Mar 9. Nat Nanotechnol. 2014. PMID: 24608229 Review.
• Electrically tunable excitonic light-emitting diodes based on monolayer WSe2 p-n junctions.

  Ross JS, Klement P, Jones AM, Ghimire NJ, Yan J, Mandrus DG, Taniguchi T, Watanabe K, Kitamura K, Yao W, Cobden DH, Xu X. Ross JS, et al. Nat Nanotechnol. 2014 Apr;9(4):268-72. doi: 10.1038/nnano.2014.26. Epub 2014 Mar 9. Nat Nanotechnol. 2014. PMID: 24608230
• Optoelectronic devices based on electrically tunable p-n diodes in a monolayer dichalcogenide.

  Baugher BW, Churchill HO, Yang Y, Jarillo-Herrero P. Baugher BW, et al. Nat Nanotechnol. 2014 Apr;9(4):262-7. doi: 10.1038/nnano.2014.25. Epub 2014 Mar 9. Nat Nanotechnol. 2014. PMID: 24608231