high tech vs high technology

high tech and high technology both are nouns.

Word	Noun	Adjective	Verb	Adverb
high tech	Yes	No	No	No
high technology	Yes	No	No	No

As nouns, high tech and high technology are synonyms defined as:

high tech and high technology: highly advanced technological development (especially in electronics)

high tech (noun)	high technology (noun)
highly advanced technological development (especially in electronics)	highly advanced technological development (especially in electronics)