Strong band edge luminescence from InN films grown on Si substrates by electron cyclotron resonance-assisted molecular beam epitaxy

Abstract

We observed strong band edge luminescence at 8.5–200 K from 200–880 nm thick InN films grown on 10 nm thick InN buffer layers on Si(001) and Si(111) substrates by electron cyclotron resonance-assisted molecular beam epitaxy. The InN film on the Si(001) substrate exhibited strong band edge photoluminescence (PL) emission at 1.814 eV at 8.5 K, tentatively assigned as donor to acceptor pair [DAP (α-InN)] emission from wurtzite-InN (α-InN) crystal grains, while those on Si(111) showed other stronger band edge PL emissions at 1.880, 2.081 and 2.156 eV, tentatively assigned as donor bound exciton [D0X(α-InN)] from α-InN grains, DAP (β-InN) and D0X (β-InN) emissions from zinc blende-InN (β-InN) grains, respectively.