Optical properties of InN/GaN quantum dot superlattice by changing dot size and interdot spacing

Abstract

InN-based III nitride quantum dot (QD) technology has attracted much attention for extended potential applications in photonic devices covering a broad spectrum compared to conventional semiconductors. In this research we have investigated electronic transitions in InN/GaN QD super-lattice structure (QDSL) from valence band (VB) to intermediate band (IB) and from IB to conduction band (CB), which cause the inter and intra band photonic absorption, leading to higher photo-generated current. The ground state energy, absorption coefficient and hence the overall device efficiency dependence on position and width of QDSL have been calculated. The time-independent Schrödinger equation with effective mass approximation in three dimensions is resolved by using Kronig-Penny approximation. The ground state energy is E0 = 1.29 eV, first excited state energy is E1 = 1.9 eV and second excited state energy is E2 = 2.4 eV in a period up to 10 QD layers. Range of transition energy is 197–1415 meV between VB and IB and CB, for which absorption coefficient is 3.5 × 105 µm−1.