Absmct.A previous shell-model-style calculation for the ground-state energy of the 'He nucleus, based on coupled cluster techniques, was able to treat exactly the centre-of-mass motion. It is now recast in a precisely equivalent but vastly more computationally efiaent form, directly in terms of coordinate-space correlation functions which are expanded in a Gaussian geminal basis and determined variationally. This reformulation further leads in a straightforward manner to a natural procedure for including higher-order correlations. Its implementation at even the simplest level produces a significant improvement in the already very good upper bounds achieved far the ground-state energy. Further extensions are also discussed.

The performance of a novel hydrogenated amorphous silicon (a-Si:H) solar cell which utilizes the field effect solar cell (FESC) has been investigated both theoretically and experimentally. The theoretical analysis has been done for both p-and n-channel FESCs by employing a two-dimensional device simulator which is based on current continuity and Poisson equations. The calculated performance is compared with that of conventional (p-in) a-Si:H solar cells. The calculation demonstrated that both n-channel and p-channel FESCs could improve the conversion effidency by as much as 50%. In order to check the reliability of simulation, the transport properties of intrinsic a-Si : H film and thin film transistor (TFT) have also been calculated and compared with the experimentally obtained characteristics. Experimental verification of TFT and FESC has been attempted by using MgO and a-SiN : H as dielectric layer materials. Preliminary results are presented.

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We have examined the impact of a simple, wet chemical postgrowth treatment of “immersing in KCN solution” on the performance of inverted staggered amorphous silicon n-channel thin film transistors. Results show that the cyanide treatment significantly improves the overall transistor performance by the elimination of defect states.