Nanosphere lithography (NSL) has emerged as an alternative nanofa

Nanosphere lithography (NSL) has emerged as an alternative nanofabrication technique, where a monodisperse or multidisperse nanosphere template acts as an etching or deposition mask to transfer its pattern to the underlying substrate [10–12]. The sizes of nanospheres can be tuned from 20 to 1,000 nm [13,

14], offering a simple and inexpensive solution to scale nanostructure feature sizes. More importantly, the location, density, GW-572016 mouse and coverage of nanostructures can be well controlled. With improvements in the domain sizes of the self-assembled nanosphere arrays [15], NSL has great potential in fabricating nanoscale electronics, optoelectronics, thermoelectrics, and biosensors. Over the past decade, NSL has been used to nanopattern Si [16], GaAs [17], and glass [18] substrates. Recently, we also demonstrated the realization of SiGe nanorod arrays on SiGe virtual substrates using NSL combined with catalytic etching [19]. On the other hand, the idea of integrating optoelectronic and electronic devices into Si chips has always been highly attractive due to the

benefits in cost, reliability, and functionality [20]. However, Si click here is an indirect bandgap semiconductor and thus of limited use for optoelectronic applications. Many efforts have been made Cobimetinib to resolve the low quantum efficiency of Si associated with its indirect bandgap. One important approach is the

combination of Si with other semiconductor materials, such as Ge or Si1 − x Ge x alloys for heterostructures. For this purpose, Si/Ge superlattices (SLs) [21], Luminespib mw multiple quantum wells (MQWs) [22], and multiple quantum dots (MQDs) [23] have been demonstrated to adjust the bandgap and reduce nonradiative recombination. Choi et al. further reported that the formation of microdisks from the Si/Ge/Si single QW using electron beam lithography significantly enhanced the intrinsic photoluminescence (PL) transitions [9]. Chen also fabricated pyramidal nanodots that possess Si/Ge SLs by chemical selective etching through a self-assembled Ge QD nanomask and found an obvious enhancement in PL emission [24]. In addition, an improvement of light extraction from SiGe/Si MQWs with nanowall structures fabricated by electron cyclotron resonance plasma etching through a random Al-masked pattern was also reported [25]. However, few studies reported the fabrication of periodic nanostructure arrays composed of SiGe/Si MQWs using NSL. In this study, we demonstrate the fabrication of optically active uniform SiGe/Si MQW nanorod and nanodot arrays from the Si0.4Ge0.6/Si MQWs using NSL combined with the reactive ion etching (RIE) process.

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