Pixelated GaSb solar cells on silicon by membrane bonding

Abstract

We demonstrate thin-film GaSb solar cells which are isolated from a GaSb substrate and transferred to a Si substrate. We epitaxially grow ∼3.3 μm thick GaSb P on N diode structures on a GaSb substrate. Upon patterning in 2D arrays of pixels, the GaSb films are released via epitaxial lift-off and they are transferred to Si substrates. Encapsulation of each pixel preserves the structural integrity of the GaSb film during lift-off. Using this technique, we consistently transfer ∼4 × 4 mm2 array of pixelated GaSb membranes to a Si substrate with a ∼ 80%–100% yield. The area of individual pixels ranges from ∼90 × 90 μm2 to ∼340 × 340 μm2. Further processing to fabricate photovoltaic devices is performed after the transfer. GaSb solar cells with lateral sizes of ∼340 × 340 μm2 under illumination exhibit efficiencies of ∼3%, which compares favorably with extracted values for large-area (i.e., 5 × 5 mm2) homoepitaxial GaSb solar cells on GaSb substrates.

All‐Group IV Transferable Membrane Mid‐Infrared Photodetectors

“…[ 6 ] One of the key features is that thin membranes can be easily transferred and integrated onto flexible, curved, or transparent substrates of virtually any material, unlocking a range of new applications in inorganic flexible, stretchable, and wearable devices. [ 7 ] As a matter of fact, semiconductor membranes are currently used as versatile building blocks in a variety of applications in thermophotovoltaics, [ 8 ] single‐cell sensing, [ 9 ] pixellated solar cells, [ 10 ] light‐emitting diodes, [ 11 ] photodetectors (PDs), [ 12,13 ] and lasers. [ 14 ] The large‐scale integration using rolling‐based direct‐transfer printing method has paved the way to mass produce these high‐performance flexible and hybrid devices.…”

“…[15] Broadband membrane photodetectors (PDs) are among the successfully implemented devices achieved using multiple materials including Si, [16,17] Ge, [18][19][20] SiGe, [21] InP, [22] InGaAs, [23] and Sb-based superlattices. [10,24] However, while these devices mainly operate at near infrared (NIR) and short-wave infrared (SWIR) wavelengths or at a longer THz wavelengths, developing membrane PDs operating in the mid-infrared (MIR) range has been severely limited by the lack of suitable material systems. 24 The ability to develop transferable MIR PDs using semiconductor released membranes is highly attractive to exploit all attributes of this platform in addition to circumventing the high-cost and limited integration of the current technologies that are based on InSb, PbSe, and HgCdTe semiconductors.…”