Richard K Ahrenkiel PhD, Owner and Chief Technical Officer.

Contract Terms; Short or long term services provided. Prices are usually on a per sample basis dependng on the quantity and type of samples provided. Discounts are available for higher volume orders.

Quotes may be obtained by email at:
or voice mail at: 303-728-9653


  • Carrier lifetime by three techniques that are contained in the Cluster Tool.
  • Carrier doping levels by means of a capacitance-voltage test station coupled to a mercury probe.

Lifetime Cluster Tool installed at LakewoodSemiconductors.

A light source chamber is shown on the left that contains small light sources such as a YAG mini-lasers. The desired beam from each source is switched into a main beam line by switching mirrors.

The first sample chamber on the left houses the Transmission Modulated Photoconductive Decay (TMPCD) apparatus that was recently patented and described in the literature

[R. K. Ahrenkiel and D. J. Dunlavy, "A new lifetime diagnostic system for photovoltaic materials", Solar Energy Materials and Solar Cells, 95 (2011), pp. 1985-1989.]

The second sample chamber from the left houses the microwave reflection photoconductive decay apparatus (µPCD). Our system uses a 10 GHz oscillator and a standard microwave splitter to measure the light generated reflection signal.

R. K. Ahrenkiel and S. W. Johnston, "Interaction of microwaves with photoelectrons in semiconductors", Journal of Vacuum Science & Technology B (Microelectronics and Nanometer Structures), v 26, n 4, p 1508-15, July 2008].

The last sample chamber on the right houses the Resonance Coupled Photoconductive Decay (RCPCD) apparatus that has been the primary apparatus for numerous publications by R. K. Ahrenkiel over the past ten years. A detailed descripiton of the apparatus was recently presented at the 2013 Photovoltaics Specialists Conference in Tampa, Florida. This apparatus is extremely sensitive to small signals and has been successfully used to measure photocurrents in low-dimensional materials.


The Company specializes in carrier lifetime measurements for private industry of university research programs. Our primary tool is resonant coupled photoconductivy decay (RCPCD). This tool was invented and developed at the National Renewable Energy Laboratory (NREL) by R. K. Ahrenkiel in the late 1990s and is still a primary characterization tool there. RCPCD is used routinely by staff to measure carrier lifetime for in-house and subcontract researchers. Lakewood Semiconductors will work with those organizations that are not eligible for NREL measurement support. We work on a contract basis usually set up on a cost/sample basis. We are able to perform these contactless measurements on a wide variety of samples of arbitrary size and shape. The technique is described in more detail in the following article:
Richard K Ahrenkiel, "Resonant Coupling For Contactless Measurement of Carrier Lifetime", J. Vac. Sci. Technol. B 31,
04D113 - 04D113-8 (2013)


Principle of Operation


Spacer operation to accommodate Resonant frequency shifts with d.c. light bias using a float zone wafer sample.



All contents copyright (c) Richard Ahrenkiel unless otherwise specified.