GaNm-plane: Atomic structure, surface bands, and optical response

A high-performance white-light-emitting-diodes based on nano-single crystal divanadates quantum dots

“…The broad band emission for white light may consist of two parts. One part is the direct band gap transition from CB to VB, and that the transition probability of this part is often the most probable15252627. While the above experimental main peak value 2.259 eV (550 nm) is in good agreement with the theoretical direct band gap result 2.25 eV, evidently proving that this direct band gap transition should be the main origination of broad band emission.…”

Ab initio hybrid DFT calculations of BaTiO3, PbTiO3, SrZrO3 and PbZrO3 (111) surfaces

“…At the same time Ti-terminated BaTiO 3 (111) surface shows strong reduction of interlayer distance d 12 , but the Ti-terminated PbTiO 3 (111) surface exhibit approximately two time smaller expansion of interlayer distance d 12 . Turning now to SrZrO 3 and PbZrO 3 perovskites, it is possible to see from Table 4 In the case of (111) surface band gap calculations, the surface states splits off from the top of the valence band and the bottom of the conduction band [55]. The band gap at the -point, namely the energy range with no electronic states between the highest occupied surface state, which split off from the top of the valence band, and lowest unoccupied surface state, which split of from the bottom of the conduction band, were calculated for BaTiO 3 Table 2).…”

Polarity-dependent pinning of a surface state

“…In contrast, for GaN(1010) the energetic position of the empty surface state was controversially debated [15], since the initial STS experiments [16,17] and calculations [17,18] found no surface state within the fundamental band gap. However, recent calculations [19][20][21][22] as well as STS experiments at very small tip-sample separations revealed a "hidden," intrinsic empty surface state within the fundamental band gap, which has a very small spatial extension into the vacuum [23]. Hence, we use GaN(1010) as an example of the group of compound semiconductors, whose nonpolar cleavage surfaces have an intrinsic surface state in the fundamental band gap.…”