Sunlight loss for femtosecond microstructured silicon with two impurity bands

Black silicon, produced by irradiating the surface of a silicon wafer with femtosecond laser pulses in the presence of a sulfur-bearing gas, is widely believed to be a potential material for efficient multi-intermediate-band silicon solar cells. Taking chalcogen as an example, we analyse the loss of sunlight for silicon with two impurity bands and we find that loss of the sunlight can be minimized to 0.332 when Te^0（0.307 eV） and Te＋（0.411 eV） are doped into microstructured silicon. Finally, problems needed to be resolved in analysing the relationship between conversion efficiency of the ideal four-band silicon solar cell and the position of the introduced two intermediated bands in silicon according to detailed balance theory are pointed out with great emphasis.

Progress and challenges in blocked impurity band infrared detectors for space-based astronomy

Astronomical detection at infrared wavelengths is crucial in astrophysics due to the critical information in this wavelength range.Blocked impurity band(BIB) infrared detectors are desirable for space-based astronomical observation due to their broad response range, low dark currents, high quantum efficiencies, and excellent radiation resistance. In this review, typical BIB device structures and device physics development are first introduced. Subsequently, we discuss progress in Si-based BIB detectors with different doping types and emphasize their applications in space-based infrared detection. Additionally, we discuss recent efforts on pixel performance optimization, response extension, and higher operating temperature devices. Finally,we conclude by proposing the challenges and perspectives of BIB detectors with improved detection performances.

ACCEPTOR IMPURITY BAND CONDUCTANCE IN ZERO-GAP Hg_(1-x)Cd_xTe

The anomalous dips A1, A2 on mobility versus temperature curves are studied in different magnetic fields. The experimental results show that A1, A2 are caused by the acceptor band conductance when the acceptor density in the conduction band is sufficiently high, and A1 is caused by mercury vacancies.

Analysis of Three Coupled Defects in One-Dimensional Photonic Bandgap Structure

The mutual interaction of three different defects in photonic crystals is studied theoretically. A theoretical model based on the classical wave analogue of the tight-binding （TB） picture is applied to the structure. We obtain analytic expressions for the eigenfrequencies and eigenmodes, from which the transmissions at resonance are derived. Based on this, a new type of the photonic quantum-well structure is investigated and its possible application is discussed. The TB predictions are compared with the transfer matrix method simulation results.

High performance infrared detectors compatible with CMOS-circuit process

A type of Si-based blocked impurity band photoelectric detector with a planar architecture is designed and demonstrated by a modified silicon semiconductor processing technique.In this route,multiple ion implantation is utilized to ensure the uniform distribution of the P elements in silicon,and rapid thermal annealing treatment is used to activate the P atoms and reduce damages caused by ion-implantation.The fabricated prototype device exhibits an excellent photoelectric response performance.With a direct current(DC)bias voltage of-2.3 V,the device detectivity to blackbody irradiation is as high as 5×10^(13)cm·Hz^(1/2)/W,which corresponds to a device responsivity of nearly 4.6 A/W,showing their potential applications in infrared detection,infrared astrophysics,and extraterrestrial life science.In particular,the developed device preparation process is compatible with that for the CMOS-circuit,which greatly reduces the manufacturing cost.