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From: berryh@udel.edu (John Berryhill)
Newsgroups: sci.electronics
Subject: Re: Blue and UltraViolet LED's
Message-ID: <24958@nigel.udel.EDU>
Date: 18 Jul 90 16:54:41 GMT
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In article <38692@cci632.UUCP> rdi@ccird3.UUCP (Rick Inzero) writes:

>I may have missed a follow-up where my question was answered, but: 
>just what's so technologically difficult here, regarding the UV LEDs?  

Finding a wide, direct bandgap semiconductor that can be doped n and p type.

Making it pure enough that midgap states won't overwhelm band-to-band
recombination (which gets exponentially tougher as the bandgap increases).

Making ohmic contact to it.

Hoping that it has mechanical and thermal properties that allow it to
tolerate operating conditions.

Finding a market for it that justifies the R&D expense.

Among others...
--
							      John Berryhill
					   143 King William, Newark DE 19711