Laser Effects On Donor Impurity In Zinc-blend Nitride Quantum Well

Since1996GaN-based blue laser has been developed for the first time, the development ofGaN-based and its alloys quantum wells, superlattices, strain composite semiconductor materials hasbrought a whole new field. Under push of such materials, quantum well lasers, high-speed two-dimensionalelectronic devices and optoelectronic integrated devices has been developed very well. Within theframework of effective-mass approximation, the effects of a laser field on the ground-state donor bindingenergy in zinc-blende (ZB) GaN/AlGaN quantum well (QW) have been investigated variationally; thecompetition effects between the laser field and applied electric field on impurity states have beeninvestigated variationally in the ZB GaN/AlGaN QW; moreover, the electric field and stepped barriereffects on hydrogenic impurity states in semiconducting stepped quantum wells (QWs) are investigatedtheoretically.Firstly, Numerical results show that the donor binding energy is highly dependent on QWstructure parameters and Al composition in ZB GaN/AlGaN QW. The laser field effects are more noticeableon the donor binding energy of an impurity localized inside the QW with small well width and low Alcomposition. However, for the impurity located in the vicinity of the well edge of the QW, the donorbinding energy is insensible to the variation of Al composition, well width and laser field intensity in ZBGaN/AlGaN QW. In particular, the competition effects between laser field and quantum confinement onimpurity states have also been investigated in this paper.Secondly, Numerical results show that for any laser field, the electric field makes the donorbinding energy present asymmetric distribution with respect to the center of the QW. Moreover, when thelaser field is weak, the electric field effects are obvious on the donor binding energy; however, the electricfield effects are insensitive to the variation of donor binding energy in the ZB GaN/AlGaN QW with stronglaser field.At last, Numerical results show that electron and impurity states are highly dependent on theelectric field and stepped barrier in the stepped QWs. The applied symmetric electric fields induceasymmetric distribution of the donor binding energy in the stepped QWs. When the electric field is applied opposite to the growth direction of stepped barrier layer, it has a remarkable influence on the donor bindingenergy of impurities located at any position in the stepped QWs with any stepped barrier height. However,when the electric field is applied along the growth direction of the stepped barrier layer, the donor bindingenergy of impurities located at any impurity position is insensitive to variation of the stepped barrier heightin the stepped QWs.In conclusion, the ground-state donor binding energy in a ZB GaN/AlGaN QW has beeninvestigated considering different impurity positions, structural parameters (well width L and Alcomposition) and laser parametersα0; it has applied electric field to investigated theoretically theground-state donor binding energy in a ZB GaN/AlGaN QW. At last, we have investigated theoreticallythe applied electric field and stepped barrier effects on hydrogenic impurity states in semiconductingstepped QWs by means of the specific ZB InGaN/GaN stepped QW case. We would like to point out thatexperimental results for applied electric field on hydrogenic impurity states in stepped QWs are still lacking,and the main results obtained in this paper might be suitable for other zinc-blende semiconductingmaterial-based QWs. We hope that the secalculation results can stimulate further investigations of thephysics and device applications.