International Business Machines Corporation

Qinglong Li

Devendra K Sadana

Ning Li

Ghavam G Shahidi

Kunal Mukherjee

Yun Seog Lee

Stephen W Bedell

A photovoltaic device including a photovoltaic cell and method of use is disclosed. The photovoltaic cell includes at least a first photovoltaic layer and a second photovoltaic layer arranged in a stack. The first photovoltaic layer has a first thickness and receives light at its top surface. A second photovoltaic layer has a second thickness and is disposed beneath the first photovoltaic layer and receives light passing through the first photovoltaic layer. The first thickness and the second thickness are selected so that a first light absorption at the first photovoltaic layer is equal to a second light absorption at the second photovoltaic layer. The photovoltaic cell is irradiated at its top surface with monochromatic light to generate a current.

Multi-junction photovoltaic cells

A semiconductor structure and a method for fabricating the same. The semiconductor structure includes a gallium arsenide substrate, a thiourea-based passivation layer in contact with at least a top surface of the gallium arsenide substrate, and a capping layer in contact with the thiourea-based passivation layer. The method includes passivating a gallium arsenide substrate utilizing thiourea to form a passivation layer in contact with at least a top surface of the gallium arsenide substrate. The method further includes forming a capping layer in contact with at least a top surface of the passivation layer, and annealing the capping layer and the passivation layer.

Thiourea organic compound for gallium arsenide based optoelectronics surface passivation

Provided is a light emitting semiconductor structure that operates as a light emitting diode (LED). In embodiments of the invention, the light emitting semiconductor structure includes a first barrier region, a second barrier region, and a single quantum well having a preselected thickness between the first barrier region and the second barrier region. The preselected thickness according to embodiments is selected to achieve a predetermined charge density in the quantum well. The predetermined charge density according to embodiments results from a predetermined bias current applied to the semiconductor structure. The predetermined bias current according to embodiments comprises less than about 1 mA.

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Bristow, VA, United States of America

Qinglong Li