Electroluminescence from n-ZnO microdisks/p-GaN heterostructure

Ultraviolet electroluminescence with electrically tunable colour from epitaxial n-(0001)ZnO/p-(0001)GaN light-emitting diodes

“…It is noticeable that the value of the non-ideality factor is found to be quite high in all cases. Note that high η values have often been reported for heterostructure devices [6,11,27,28] and attributed to barrier inhomogeneity, interface states, leakage due to tunnelling and non-uniform distribution of carriers at the interface [29,30]. Since all of our samples exhibit good epitaxial and interface qualities, it is unlikely that above factors are responsible for the high values of η obtained here.…”

“…Emission of light in the wavelength range of 390-415 nm has also been observed from these devices [5,[8][9][10]. Recently Ai et al [3] and Turko et al [11] have reported UV light emission from n-ZnO/p-GaN heterojunction LEDs that peak at ∼376 nm and 366 nm, respectively. However, in most of these studies, very little have been done to understand the origin of the UV emissions and the influence of the crystalline quality of the heterostructure on the device performance.…”

“…We believe that the reason for the high non-ideality of our samples is the presence of the Schottky barrier at the metal contact with the p-GaN side as discussed earlier (see figure 4(b)). It has also been reported that such large variation of η value may be attributed to the quality of contacts [11].…”

High responsivity n-ZnO nanorods/p-GaN heterojunction-based UV-A photodetectors

“…Among various wide bandgap semiconductors such as AlN, ZnO, BN, NiO, TiO 2 , Cu 2 O, and ZnS in which ZnO has attracted much wider attention from the scientific community, especially for UV photodetectors due to its interesting optoelectronic properties such as large exciton binding energy, inherent UV to visible absorption rejection ratio, etc [2]. Moreover, the large bandgap of 3.37 eV makes ZnO, a promising candidate for UV detection [7,8]. Additionally, the biocompatible nature of the ZnO and essay to fabricate thin films and nanostructures made additional advantages over other contenders for optoelectronic applications.…”

Optical properties of composite structure based on ZnO microneedles and Alq3 thin film

“…The most challenging problem of the electrooptic devices based on ZnO homojunction is the lack of stable and reliable p-type doping [7]. In this situation, ZnO-based LEDs usually are fabricated by combining of n-type ZnO with a p-type semiconductor other than ZnO, for example, Cu 2 O, ZnTe, SrCu 2 O 2 , AlGaN, GaN or p-type conduction polymers [7,9]. To our knowledge, there are quite a number of publications devoted separately to ZnO and Alq 3 , while composite materials based on them have been studied by only a few research teams from India [10][11][12][13][14][15], China [16,17], Swiss [18], Republic of Korea [19] and Japan [20].…”